* stable-2.15:
Fix "Group members can't be added as reviewers" after merging
Set version to 2.15-SNAPSHOT
ProjectLevelConfig: Import Collectors.toList static
Merge parent config values with child values
Set version to 2.14.8-SNAPSHOT
Fix the missing DB entry in Gerrit DB
Fix unit test "addGroupAsReviewersWhenANotPerfectMatchedUserExist"
Change-Id: I18e635f55f69892b1c5c9f203030f4181973fa3c