ils-video-recorder:fix None exception

ils_common_video/isc_video/recorder.py

@@ -221,7 +221,7 @@ class ProcessMessage:
 
         now = datetime.now()
         url = next_retry_time = None
-        remark = event.get('remark')
+        remark = event.get('remark','')
         status = 2
         file_name = record_result['file_name'].split('/')[-1]