cluster xlators: s/-1/GF_CLIENT_PID_GSYNCD/

Change-Id: I03be3cb23684de4ab36cf2953002708466edd580
BUG: 765433
Signed-off-by: Csaba Henk <csaba@redhat.com>
Reviewed-on: http://review.gluster.org/4601
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>