Adding the Gerrit hooks and support scripts to git

Change-Id: I836cde096ab56c64704c78b7bff21a2f349e3adb
Reviewed-on: http://review.couchbase.org/34227
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>