Remove gather_googlevideo_domains setting

This was an old experiment to collect googlevideo domains to see
if there was a pattern that could correlate to IP address to
look for workarounds for 403 errors

Can bug out if enabled and if failed to get any vidoe urls,
so remove since it is obsolete and some people are enabling it

See #218

youtube/watch.py

@@ -649,12 +649,6 @@ def get_watch_page(video_id=None):
             '/videoplayback',
             '/videoplayback/name/' + filename)
 
-    if settings.gather_googlevideo_domains:
-        with open(os.path.join(settings.data_dir, 'googlevideo-domains.txt'), 'a+', encoding='utf-8') as f:
-            url = info['formats'][0]['url']
-            subdomain = url[0:url.find(".googlevideo.com")]
-            f.write(subdomain + "\n")
-
     download_formats = []
 
     for format in (info['formats'] + info['hls_formats']):