Style fixes in YoutubeDL.py

Fixed some of the problems reported by pep8

youtube_dl/YoutubeDL.py

@@ -278,7 +278,7 @@ class YoutubeDL(object):
             sanitize = lambda k, v: sanitize_filename(
                 u'NA' if v is None else compat_str(v),
                 restricted=self.params.get('restrictfilenames'),
-                is_id=(k==u'id'))
+                is_id=k == u'id')
             template_dict = dict((k, sanitize(k, v)) for k, v in template_dict.items())
 
             filename = self.params['outtmpl'] % template_dict