Postprocessor doesn't work for reactor

[dawidsowa]

Steps to reproduce

Write config.json as:

{
  "extractor": {
    "reactor": {
      "postprocessors": [
        {
          "name": "exec",
          "command": "echo {}"
        }
      ]
    }
  }
}

Run gallery-dl 'http://anime.reactor.cc/post/3576250' -q and gallery-dl 'http://joyreactor.com/post/3721876' -q.

Expected behavior

Both commands should return paths.

Actual behavior

There's no output.

Additional Info

Changing reactor in config.json to joyreactor makes the second command behave as expected and return path.

Changing content of config.json to

{
  "extractor": {
    "postprocessors": [
      {
        "name": "exec",
        "command": "echo {}"
      }
    ]
  }
}

makes both commands run as expected