Revert "disable YT ratelimit; this should enable to max out the connection bandwidth"

Although cool, that seems to break a lot of youtube videos.

This reverts commit a60b854d90.

youtube_dl/InfoExtractors.py

@@ -581,7 +581,7 @@ class YoutubeIE(InfoExtractor):
             url_data_strs = video_info['url_encoded_fmt_stream_map'][0].split(',')
             url_data = [compat_parse_qs(uds) for uds in url_data_strs]
             url_data = [ud for ud in url_data if 'itag' in ud and 'url' in ud]
-            url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0] + '&ratebypass=yes') for ud in url_data)
+            url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0]) for ud in url_data)
 
             format_limit = self._downloader.params.get('format_limit', None)
             available_formats = self._available_formats_prefer_free if self._downloader.params.get('prefer_free_formats', False) else self._available_formats