* stable-2.15:
Set version to 2.15.12-SNAPSHOT
Set version to 2.15.11
Allow LFS-over-SSH created auth pass through ContainerAuthFilter
Upgrade elasticsearch-rest-client to 6.6.1
ElasticContainer: Bump the test server version to 5.6.15
Change-Id: I6a54f5b233cf9fa6053241b729cdd300f83dfdc9