Merged revision(s) 1470975 from lucene/dev/trunk:
LUCENE-4949: Make the version prefix ("SNAPSHOT") separately configurable to enable Jenkins use its BUILD_ID variable, cleanup code duplication

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1470978 13f79535-47bb-0310-9956-ffa450edef68