tests: Moving sleep call after action in ceph_watch_wait()

ceph_watch_wait() is doing a sleep _before_ doing the test which could
stop this loop.

It's better doing the action first as it could exit immediately and
avoid a useless sleep.

That's a minor optimization but everything count when trying to get
something smooth.

Signed-off-by: Erwan Velu <erwan@redhat.com>

qa/workunits/cephtool/test.sh

@@ -170,8 +170,8 @@ function ceph_watch_wait()
     fi
 
     for i in `seq ${timeout}`; do
-	sleep 1
 	grep -q "$regexp" $CEPH_WATCH_FILE && break
+	sleep 1
     done
 
     kill $CEPH_WATCH_PID