[youtube] Only set language when necessary

We only need to set the language when we are using a login; otherwise it will always be English.

youtube_dl/extractor/youtube.py

@@ -191,8 +191,9 @@ class YoutubeBaseInfoExtractor(InfoExtractor):
     def _real_initialize(self):
         if self._downloader is None:
             return
-        if not self._set_language():
+        if self._get_login_info()[0] is not None:
-            return
+            if not self._set_language():
+                return
         if not self._login():
             return
         self._confirm_age()