[ffmpeg] Remove trivial helper method

youtube_dl/postprocessor/ffmpeg.py

@@ -37,7 +37,7 @@ class FFmpegPostProcessor(PostProcessor):
         if not self.available:
             raise FFmpegPostProcessorError('ffmpeg or avconv not found. Please install one.')
 
-        required_version = '10-0' if self._uses_avconv() else '1.0'
+        required_version = '10-0' if self.basename == 'avconv' else '1.0'
         if is_outdated_version(
                 self._versions[self.basename], required_version):
             warning = 'Your copy of %s is outdated, update %s to version %s or newer if you encounter any errors.' % (
@@ -112,9 +112,6 @@ class FFmpegPostProcessor(PostProcessor):
     def available(self):
         return self.basename is not None
 
-    def _uses_avconv(self):
-        return self.basename == 'avconv'
-
     @property
     def executable(self):
         return self._paths[self.basename]