[auengine] Simplify

youtube_dl/extractor/auengine.py

@@ -24,8 +24,7 @@ class AUEngineIE(InfoExtractor):
     }
 
     def _real_extract(self, url):
-        mobj = re.match(self._VALID_URL, url)
-        video_id = mobj.group('id')
+        video_id = self._match_id(url)
 
         webpage = self._download_webpage(url, video_id)
         title = self._html_search_regex(r'<title>(?P<title>.+?)</title>', webpage, 'title')