CBIT-598:  use local mirror instead of github for couchbase repos

Change-Id: I04adaab1178b748f52abfdad8e5ae70c944a2a4a
Reviewed-on: http://review.couchbase.org/28980
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>