We are affected by GROOVY-8067
We are affected by GROOVY-8067

Groovy-8067 fixed a deadlock issue in ClassInfo entry, c.f.
  https://issues.apache.org/jira/browse/GROOVY-8067

Bump groovy version to 2.4.15.

Signed-off-by: Qun Li <1ea81f54854048d0a4d4fd61caceabb2a843281c@zstack.io>

MatheMatrix/zstack,AlanJager/zstack,AlanJager/zstack,zstackorg/zstack,MatheMatrix/zstack,zstackio/zstack,MatheMatrix/zstack,zstackorg/zstack,zstackio/zstack,AlanJager/zstack,zstackio/zstack