LU-358 Add the branch and commiti-id to the yml.

LU-358 Add the branch and commiti-id to the yml.

yaml.sh updated to provide the information requested in the JIRA the
change is simple and requires that LUSTRE_BRANCH and LUSTRE_REVISION
are defined, if they are not defined then the elements are left blank

Signed-off-by: Chris Gearing <chris@whamcloud.com>
Change-Id: Id18f3d5c68d3703af3b76628d7d43289c57bf485
Reviewed-on: http://review.whamcloud.com/1400
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Johann Lombardi <johann@whamcloud.com>