improve error handling + fix muc

ejabberdrpc.py

@@ -20,6 +20,7 @@ class EjabberdMetrics():
         else:
             self._url = url
             self._cmd = self._rest
+
     @property
     def _auth(self):
         if self._login is not None:
@@ -29,7 +30,7 @@ class EjabberdMetrics():
 
     def _rest(self, command, data):
         r = requests.post("%s/%s" % (self._url, command), auth=self._auth, json=data)
-        if r is not None:
+        if r.status_code == 200:
             return r.json()
         return {}
 
@@ -141,6 +142,7 @@ class EjabberdMetrics():
         result = self._cmd("muc_online_rooms", {"host": host})
         if "rooms" in result:
             return len(result["rooms"])
+        return len(result)
 
     def update(self):
         # nodes