Add condition for API failure (#7181)

* Add condition for API failure

If you are not running the latest ve3rsion of ZM this will cause exceptions to fire. This fix handles a response from ZM but a non successful attempt. 

This resolves the issue https://github.com/home-assistant/home-assistant/issues/7178

* Fixed houndci-bot issues

homeassistant/components/camera/zoneminder.py

@@ -101,11 +101,17 @@ class ZoneMinderCamera(MjpegCamera):
         status_response = zoneminder.get_state(
             'api/monitors/alarm/id:%i/command:status.json' % self._monitor_id
         )
+
         if not status_response:
             _LOGGER.warning('Could not get status for monitor %i',
                             self._monitor_id)
             return
 
+        if status_response['success'] is False:
+            _LOGGER.warning('Alarm status API call failed for monitor %i',
+                            self._monitor_id)
+            return
+
         self._is_recording = status_response['status'] == ZM_STATE_ALARM
 
     @property