In the event when there are no available sources due to DRM controlled sources, return a DRM error and don't proceed with trying.
#28 reports that an ExtractorError "No video formats found". Which is true, because the formats list is empty, however it's empty because they are all locked. This provides a more informative message to the end-user.
Tried the URL provided in #28 and confirmed a DRM messages is returned.
Fix a problem introduced in 320724f964 where is extracted the ID from the url with self._match_id but the problem is that ID is not always present in the url passed so the title should be extracted as proposed by the fix (and like is done in _real_extract (see line 337))