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
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 1f41431..710147b 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -479,7 +479,8 @@
             container_key,
             key_passwords[container_key],
             codename_to_api_level_map,
-            OPTIONS.avb_extra_args.get('apex'))
+            no_hashtree=True,
+            signing_args=OPTIONS.avb_extra_args.get('apex'))
         common.ZipWrite(output_tf_zip, signed_apex, filename)
 
       else: