youtube-dl fails on some videos with error: ValueError: dictionary update sequence element #0 has length 1; 2 is required

[Elizafox]

On some videos, such as http://www.youtube.com/watch?v=21UP0frYg-E, youtube-dl generates the following error:

[elizabeth@ein ~]$ youtube-dl http://www.youtube.com/watch?v=21UP0frYg-E
--- 8< snip >8 ---
[youtube] 21UP0frYg-E: Extracting video information
Traceback (most recent call last):
  File "/usr/bin/youtube-dl", line 2985, in 
    retcode = fd.download(all_urls)
  File "/usr/bin/youtube-dl", line 604, in download
    ie.extract(url)
  File "/usr/bin/youtube-dl", line 844, in extract
    return self._real_extract(url)
  File "/usr/bin/youtube-dl", line 1083, in _real_extract
    url_map = dict(tuple(pair.split('|')) for pair in video_info['fmt_url_map'][0].split(','))
ValueError: dictionary update sequence element #0 has length 1; 2 is required

Having done some investigation into the issue, it appears video_info does not get returned with the fmt_url_map element on some videos.

[rg3]

Closing as it's a dupe of #86.