Tolerate junk at the end of gzip-compressed content (#1268)
Merge branch 'master' of github.com:rg3/youtube-dl
[generic] Fix URL concatenation

When the url is something like http://example.org/foo/bar?x=y  and the added is file/video.mp4 , we want http://example.org/foo/file/video.mp4
Fixes #1268.
Merge remote-tracking branch 'upstream/master'