YouTube: Fall back to <meta> description if video is rated (Fixes #800)

youtube_dl/InfoExtractors.py

@@ -569,6 +569,10 @@ class YoutubeIE(InfoExtractor):
         video_description = get_element_by_id("eow-description", video_webpage)
         if video_description:
             video_description = clean_html(video_description)
+        else:
+            fd_mobj = re.search(r'<meta name="description" content="([^"]+)"', video_webpage)
+            if fd_mobj:
+                video_description = unescapeHTML(fd_mobj.group(1))
             else:
                 video_description = u''