Do not require arguments for os-svc-daemon.

They are not actually required, so allow os-svc-daemon to be called
without them.

Change-Id: I62c2887d48e4173005c54c9cab4ecd6aff8069a1

elements/os-svc-install/bin/os-svc-daemon

@@ -23,7 +23,7 @@ exec start-stop-daemon --start -c $user --exec /opt/stack/venvs/$user/bin/$cmd $
 EOF
 }
 
-if [ $# -lt 4 ]; then
+if [ $# -lt 3 ]; then
   echo "Usage: os-svc-daemon DAEMON_NAME USER COMMAND [ARG[ARG[...]]]"
   exit 1
 fi