Merge "Fix problem of RepackApexPayload when using option --signing_args" into main

    # --signing_args "--signing_helper_with_files=%path" to apexer

    if signing_args:

      generate_image_cmd.extend(

          ['--signing_args', '"{}"'.format(signing_args)])

          ['--signing_args', signing_args])

    # optional arguments for apex repacking

    manifest_json = os.path.join(apex_dir, 'apex_manifest.json')