SLING-3286 - Remove plugin version overrides from poms

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1551065 13f79535-47bb-0310-9956-ffa450edef68
SLING-3286 - Remove plugin version overrides from poms

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1551066 13f79535-47bb-0310-9956-ffa450edef68