correct error in variable name

lib_stov/subscription.py

@@ -89,7 +89,7 @@ class sub(object):
             for video in self.__video_list:
                 if video.downloaded == 0:
                     if video.DownloadVideo(self.__directory, itag_value,
-                                           self.__conf["videocodec"]):
+                                           self.__conf.values["videocodec"]):
                         self.DownloadedVideos.append(video)
                     else:
                         self.FailedVideosCount += 1