Updated wercker file

grafana

@@ -1 +1 @@
-Subproject commit 318338f967a4c89cceaa1d1ca7b6a8e6de383f9f
+Subproject commit 55bc1507013279ed526c235c343885b49fe441e7

wercker.yml

@@ -28,5 +28,5 @@ build:
         cwd: grafana/
     - grunt:
         cwd: grafana/
-        tasks: release
+        tasks: release --mode==backend