message: dont delete metadata in api21mode unpackage
  Summary:
  build[automation_fbandroid_]
  Need the metadata.txt intact for redex-tool (e.g. dexsql etc)
diff: @@ -188,9 +188,6 @@ class Api21DexMode(BaseDexMode):
  BaseDexMode.unpackage(self, extracted_apk_dir, dex_dir)
  metadata_dir = join(extracted_apk_dir, self._secondary_dir)
  - jar_meta_path = join(metadata_dir, 'metadata.txt')
  - if os.path.exists(jar_meta_path):
  - os.remove(jar_meta_path)
  if self._is_root_relative:
  extracted_dex_dir = extracted_apk_dir
  else:
  