Exception while decoding some soundcloud urls

Some of the soundcloud urls generate JSON exception

I think the response code for http call is 401, and some links have additional protection

Example links:

• https://soundcloud.com/goldfishlive/ultra-miami-set-2017-live-stage-goldfish
• https://soundcloud.com/lane8music/lane-8-spring-2017-mixtape
• https://soundcloud.com/solomun/bbc-1-essential-mix-live-live-from-solomun1-at-pacha-ibiza

Traceback:

(soundscrape) ❯ soundscrape https://soundcloud.com/goldfishlive/ultra-miami-set-2017-live-stage-goldfish
Traceback (most recent call last):
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/bin/soundscrape", line 11, in <module>
    sys.exit(main())
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/soundscrape/soundscrape.py", line 119, in main
    process_soundcloud(vargs)
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/soundscrape/soundscrape.py", line 198, in process_soundcloud
    hard_track_url = get_hard_track_url(item_id)
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/soundscrape/soundscrape.py", line 518, in get_hard_track_url
    json_response = response.json()
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/requests/models.py", line 866, in json
    return complexjson.loads(self.text, **kwargs)
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/simplejson/__init__.py", line 516, in loads
    return _default_decoder.decode(s)
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/simplejson/decoder.py", line 374, in decode
    obj, end = self.raw_decode(s)
  File "/Users/jakubzygmunt/.virtualenvs/soundscrape/lib/python2.7/site-packages/simplejson/decoder.py", line 404, in raw_decode
    return self.scan_once(s, idx=_w(s, idx).end())
simplejson.scanner.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Start in soundscrape.py at process_soundcloud and get_hard_track_url, identified by the traceback. Reproduce the failure with one of the example SoundCloud URLs and inspect the HTTP response before response.json() is called. Done means these responses no longer produce an uncaught JSONDecodeError and the behavior for the affected URLs is handled appropriately.