Change JDK used by Buildship

[st_oehme (Stefan Oehme)]

@jpw-erigo

Buildship 2.0 has the capability to specify an updated JDK without the need to re-import the project

No, Buildship 2.0 will not have the JDK option at all, since the JDK for Gradle can already be defined in ~/.gradle/gradle.properties.