Add restart_builddocker.py script

Change-Id: I9a911c75f8ad565229d6a32f7c818d753ef24e9b
Reviewed-on: http://review.couchbase.org/40529
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>