Adds property buildsToKeep.

Change-Id: I8e0bf41af1b8f0c0559b2197aef4287ce065a41e
Reviewed-on: https://git.eclipse.org/r/18423
Reviewed-by: Ken Lee <kle@bsiag.com>
IP-Clean: Ken Lee <kle@bsiag.com>
Tested-by: Ken Lee <kle@bsiag.com>
3 files changed