Use the right service name for tgt/tgtd in stop_cinder

Change-Id: I58cf8cdf88a3edebed729f4460e8ce222db3664d
diff --git a/lib/cinder b/lib/cinder
index 16cbaf3..586cfcb 100644
--- a/lib/cinder
+++ b/lib/cinder
@@ -265,7 +265,11 @@
     done
 
     if is_service_enabled c-vol; then
-        stop_service tgt
+        if is_ubuntu; then
+            stop_service tgt
+        else
+            stop_service tgtd
+        fi
     fi
 }