Fixed issue with log entries without exception stack

bazarr/api.py

@@ -521,6 +521,7 @@ class SystemLogs(Resource):
                 log["timestamp"] = lin[0]
                 log["type"] = lin[1].rstrip()
                 log["message"] = lin[3]
+                if len(lin) > 4:
                     if lin[4] != '\n':
                         log['exception'] = lin[4].strip('\'').replace('  ', '\u2003\u2003')
                 logs.append(log)