osx: LaunchDaemon plist filename should start with org instead of com

Backport of http://review.gluster.org/8734

BUG: 1141665
Change-Id: Ia41b00f3c49644f6a3c12e76c2395fce117c1bee
Signed-off-by: Justin Clift <justin@gluster.org>
Reviewed-on: http://review.gluster.org/8735
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
Tested-by: Harshavardhana <harsha@harshavardhana.net>
Tested-by: Gluster Build System <jenkins@build.gluster.com>