Merge "--sign_tool is an optional flag applicable to virtApex." am: ff3a1c73cf

Original change: https://android-review.googlesource.com/c/platform/build/+/1933021

Change-Id: I121cb833348795c7dc64ef774456da8e171fb5bc

tools/releasetools/sign_apex.py

@@ -141,7 +141,7 @@ def main(argv):
       signing_args=options.get('payload_extra_args'),
       codename_to_api_level_map=options.get(
           'codename_to_api_level_map', {}),
-      sign_tool=options['sign_tool'])
+      sign_tool=options.get('sign_tool', None))
   shutil.copyfile(signed_apex, args[1])
   logger.info("done.")