MB-7250:  sign at project level:

CODE_SIGN_IDENTITY   = "3rd Party Mac Developer Application";
PROVISIONING_PROFILE = "3B464580-5CE0-4BF8-B3E0-7D0F892408B8";

Change-Id: Ie42b8468761f50e1251fd66236809024d1ec3c80
Reviewed-on: http://review.couchbase.org/28777
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>