git: Fix git.CreatePushBranch calls with remote_push_branch.

Two more locations broken by my CL:262443 to clean up lint problems in
git.py.

BUG=chromium:473432
TEST=Lint + unittests (where present)

Change-Id: Iba0a6a37aa2f33c96921cd504c59f6f39210ad9e
Reviewed-on: https://chromium-review.googlesource.com/263815
Trybot-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Rohit Makasana <rohitbm@chromium.org>
Commit-Queue: Don Garrett <dgarrett@chromium.org>
diff --git a/scripts/cros_merge_to_branch.py b/scripts/cros_merge_to_branch.py
index 02d2666..a2fc8e8 100644
--- a/scripts/cros_merge_to_branch.py
+++ b/scripts/cros_merge_to_branch.py
@@ -183,7 +183,7 @@
   # branch.
   git.CreatePushBranch(
       constants.PATCH_BRANCH, work_dir, sync=False,
-      remote_push_branch=('ignore', 'origin/%s' % branch))
+      remote_push_branch=git.RemoteRef('ignore', 'origin/%s' % branch))
 
   return branch