Java-library-distribution issue in gradle

I am using apply plugin: ‘java-library-distribution’ in my build.gradle script to create the zip file It is working perfectly .One thing which I noticed here is after unzipping my zip file it creates the same folder inside the same folder.

Below is the output of the tree command which shows after unzipping the zip file I saw AnalyticsLib-4.0.0 and again there is one folder with same name AnalyticsLib-4.0.0 which is wired.Can someone tell me what is the issue?After unzip it should show only AnalyticsLib-4.0.0----Lib folder

C:.
└───AnalyticsLib-4.0.0
└───AnalyticsLib-4.0.0
└───lib

Below is my gradle script



   apply plugin: 'jacoco'
    apply plugin: 'findbugs'
    apply plugin: 'pmd'
    apply plugin: 'checkstyle'
    apply plugin: 'maven'
    apply plugin: 'java-library-distribution'
    
    //-- set the group for publishing
    group = 'com.tru.analyticsengine'
    
    /**
     * Initializing GAVC settings
     */
    def buildProperties = new Properties()
    file("version.properties").withInputStream { 
    	stream -> buildProperties.load(stream) 
    } 
    //add the jenkins build version to the version
    def env = System.getenv()
    if (env["BUILD_NUMBER"]) buildProperties.analyticsengineBuildVersion += ".${env["BUILD_NUMBER"]}"
    version = buildProperties.analyticsengineBuildVersion
    println "${version}"
    
    //name is set in the settings.gradle file
    group = "com.truvenhealth.analyticsengine"
    version = buildProperties.analyticsengineBuildVersion
    println "Building ${project.group}:${project.name}:${project.version}"
    
    sourceCompatibility = 1.7
    compileJava.options.encoding = 'UTF-8'
    
    repositories {
         maven { url "http://cm.t.t.com:8/artifactory/libs-snapshot" }   
         maven { url "http://cm.t.t.com:8/artifactory/libs-release" }
    	 maven { url "http://cm.t.t.com:8/artifactory/libs-stage" }
         maven { url "http://cm.t.t.com:8/artifactory/simple/ext-release-local/" }
      }
    dependencies {
        compile group: 'com.truv.analyticsengine', name: 'common', version:'4.0.0.94'
        compile group: 'com.truv.analyticsengine', name: 'LicenseVerifier', version:'4.0.0.89'
    	compile group: 'com.truv.analyticsengine', name: 'MegNativeJNI', version: '4.0.0.84', ext: 'so'
    	compile group: 'com.truv.analyticsengine', name: 'NativeJNI', version: '4.0.0.97', ext: 'so'
        compile(group: 'com.operasolutions', name: 'RiskAnalytics', version:'1.1') {
    exclude(module: 'jyson')
        }
        compile group: 'org.springframework', name: 'spring-context', version:'3.2.5.RELEASE'
        compile group: 'org.springframework', name: 'spring-beans', version:'3.2.5.RELEASE'
        compile group: 'org.springframework', name: 'spring-core', version:'3.2.5.RELEASE'
        compile group: 'org.springframework', name: 'spring-aop', version:'3.2.5.RELEASE'
        compile group: 'org.springframework', name: 'spring-expression', version:'3.2.5.RELEASE'
        compile group: 'org.apache.commons', name: 'commons-collections4', version:'4.0'
        compile group: 'commons-io', name: 'commons-io', version:'2.4'
        compile group: 'net.sf.supercsv', name: 'super-csv-dozer', version:'2.1.0'
        compile group: 'net.sf.supercsv', name: 'super-csv', version:'2.1.0'
        compile group: 'org.aspectj', name: 'aspectjtools', version:'1.6.2'
        compile group: 'org.python', name: 'jython-standalone', version:'2.5.3'
        compile group: 'com.google.code.gson', name: 'gson', version:'1.7.2'
        compile group: 'log4j', name: 'log4j', version:'1.2.16'
        compile group: 'com.xhaus', name: 'jyson', version:'1.0.2'
        compile group: 'com.google.guava', name: 'guava', version:'17.0'
        compile group: 'com.jamonapi', name: 'jamon', version:'2.4'
        compile group: 'ch.qos.logback', name: 'logback-classic', version:'1.1.1'
        compile group: 'ch.qos.logback', name: 'logback-core', version:'1.1.1'
        compile group: 'org.slf4j', name: 'slf4j-api', version:'1.7.6'
        compile group: 'org.codehaus.mojo', name: 'properties-maven-plugin', version:'1.0-alpha-2'
        compile group: 'args4j', name: 'args4j', version:'2.0.28'
        compile group: 'org.codehaus.jackson', name: 'jackson-mapper-asl', version:'1.9.5'
        testCompile group: 'junit', name: 'junit', version:'4.11'
        testCompile group: 'org.mockito', name: 'mockito-all', version:'1.9.5'
    }
       
    jacoco {
        toolVersion = "0.7.1.201405082137"
    }
    test {
        jacoco {
            append = false
            destinationFile = file("$buildDir/jacoco/jacocoTest.exec")
            classDumpFile = file("$buildDir/jacoco/classpathdumps")
        }
    }
    
    jacocoTestReport {
    	group = "Reporting"
    	description = "Generate Jacoco coverage reports after running tests."
    	executionData = fileTree(dir: 'build/jacoco', include: '**/*.exec')
    
    	reports {
    		xml{
    			enabled true
    			//Following value is a file
    			destination "${buildDir}/reports/jacoco/xml/jacoco.xml"
    		}
    		csv.enabled false
         html{
           enabled true
           //Following value is a folder
           destination "${buildDir}/reports/jacoco/html"
         }
    	}
    }
    	
    findbugs {
            ignoreFailures = true
           //sourceSets = [sourceSets.main]
       }
       
    pmd { 
             ruleSets = ["java-basic", "java-braces", "java-design"] 
             ignoreFailures = true
             //sourceSets = [sourceSets.main]
       }
     
    checkstyle {
          configFile = new File(rootDir, "config/checkstyle.xml")
          ignoreFailures = true
          //sourceSets = [sourceSets.main]
       }
       
     // adding test report to taskGraph
    build.dependsOn jacocoTestReport
    
    def pomFile = file("${buildDir}/libs/${archivesBaseName.toLowerCase()}-${version}.pom")
    task newPom << {
        pom {
          project {
              groupId project.group
              artifactId project.name
              version project.version
              description = "Configuration Management Gradle Plugin"
          }
      }.writeTo(pomFile)
    }
    // adding pom generation to taskGraph
    build.dependsOn newPom
    
    //disabling the install task since we're not using maven for real
    install.enabled = false
    
    //for publishing to artifactory via jenkins
    if(project.hasProperty('artifactoryPublish')) {
      artifactoryPublish {
        mavenDescriptor pomFile
      }
    }
       
    jar {
        // Keep jar clean:
        exclude 'META-INF/*.SF', 'META-INF/*.DSA', 'META-INF/*.RSA', 'META-INF/*.MF'
        manifest {
            attributes 'Manifest-Version': '1.0',
    		           'Build-Jdk': '1.7.0_45',
                       'Class-Path': configurations.compile.files.collect { "lib/$it.name" }.join(' ')
        }
     }
    
     // ------ Publish the jar file to artifactory ------
    artifacts {
      distZip
      newPom
       }