Revert "Fix problem of RepackApexPayload when using option --signing_args"

This reverts commit 5ebc4febe6.

Reason for revert: This is causing the signing args to be improperly passed to apexer, treating them as if they are not specified as all.

Change-Id: Ifa0f8444a4a1871802316511b0ff0735f3350b2c
Bug: 361784913

tools/releasetools/apex_utils.py

@@ -198,7 +198,7 @@ class ApexApkSigner(object):
     # --signing_args "--signing_helper_with_files=%path" to apexer
     if signing_args:
       generate_image_cmd.extend(
-          ['--signing_args', signing_args])
+          ['--signing_args', '"{}"'.format(signing_args)])
 
     # optional arguments for apex repacking
     manifest_json = os.path.join(apex_dir, 'apex_manifest.json')