Don't generate hashtree when signing bundled APEXes.

Bug: 139957269
Test: Sign a target_files.zip. Extract a re-signed APEX and check the
      hashtree size (being zero).
Test: Use sign_apex to sign an APEX file. Check the hashtree size (not
      being zero).
Test: python -m unittest test_apex_utils
Test: python -m unittest test_sign_apex
Change-Id: I927b7681d66920d7732b700ec3a8f7a65b4cb351

tools/releasetools/sign_apex.py

@@ -56,6 +56,7 @@ def SignApexFile(avbtool, apex_file, payload_key, container_key,
       container_key=container_key,
       container_pw=None,
       codename_to_api_level_map=None,
+      no_hashtree=False,
       signing_args=signing_args)
 
 
@@ -103,7 +104,8 @@ def main(argv):
       args[0],
       options['payload_key'],
       options['container_key'],
-      options.get('payload_extra_args'))
+      no_hashtree=False,
+      signing_args=options.get('payload_extra_args'))
   shutil.copyfile(signed_apex, args[1])
   logger.info("done.")