message: Check that the lib dir exists when extracting xz
  Summary: Check if the lib dir exists before trying to extract `libs.xzs`.
diff: @@ -570,8 +570,9 @@ def run_redex(args):
  # xz-compressed file. We need to decompress that file so that we can scan
  # through it looking for classnames.
  xz_compressed_libs = join(extracted_apk_dir, 'assets/lib/libs.xzs')
  - temporary_lib_file = join(extracted_apk_dir, 'lib/concated_native_libs.so')
  - if os.path.exists(xz_compressed_libs):
  + libs_dir = join(extracted_apk_dir, 'lib')
  + temporary_lib_file = join(libs_dir, 'concated_native_libs.so')
  + if os.path.exists(xz_compressed_libs) and os.path.exists(libs_dir):
  cmd = 'xz -d --stdout {} > {}'.format(xz_compressed_libs, temporary_lib_file)
  subprocess.check_call(cmd, shell=True)
  