CBD-1217:  use function to get repo builder name

Change-Id: Idb7e3f34cbe139512f1fd45c9a6294fd512c7470
Reviewed-on: http://review.couchbase.org/33216
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>