Excluding a module from configuration in subproject not wokring

I have got a gradle project (gradle 2.0), with multiple sub-projects, and I am adding a new sub-project (which in it self is having sub-projects) and the settings.gradle looks something like -

include ':subproject-a',

The root build.gradle is adding a org.codehaus.jackson module dependency, coming from a predefined configuration TestConfig

Root level build.gradle >>

allprojects {
     integTestCompile configurations.TestConfig
     //all other dependencies and configurations are applied to all sub-projects in integTestCompile

Now as part of my subproject - “my_new_sub_project-rohan”, I want to exclude the entire module org.codehaus.jackson, but even after writing the below exclude statement, it is not getting excluded.

my_new_sub_project-rohan level build.gradle >>

subprojects {
    configure ( subprojects.findAll {}) {
        afterEvaluate {
            configurations.all {
                exclude group: 'org.codehaus.jackson', module: 'jackson-core-asl'
                exclude group: 'org.codehaus.jackson', module: 'jackson-mapper-asl'

But even then, this module is getting added to classpath. I checked by running
$> gradle dependencies
and this org.codehuas.jackson module still listed there.

Any inputs on something I am doing incorrectly or may be on how to achieve the exclusion ?

Thanks. Appreciate any inputs.