Failure during /sync

```
11:05:07 matrix =!= | Error in http_cb: /home/jeremy/.weechat/lua/autoload/matrix.lua:2181:badargument#1to'match'(stringexpected,
                     | got nil)
11:05:07 matrix =!= | stack traceback:
11:05:07 matrix     | /home/jeremy/.weechat/lua/autoload/matrix.lua:825: in function </home/jeremy/.weechat/lua/autoload/matrix.lua:821>
```