[unistra] Sort formats

Originally URLs are passed to set() and not sorted, so the result is not
deterministic, causing occasional FAILs on Travis CI.

youtube_dl/extractor/unistra.py

@@ -49,6 +49,7 @@ class UnistraIE(InfoExtractor):
                 'format_id': format_id,
                 'quality': quality(format_id)
             })
+        self._sort_formats(formats)
 
         title = self._html_search_regex(
             r'<title>UTV - (.*?)</', webpage, 'title')