[Sync::USS] Rename syncPositioningScheme in ModelTypeWorker

Change-Id: I04dcc33b375f552a8e4e6dbc8b5ae75869ddfa08
Reviewed-on: https://chromium-review.googlesource.com/c/1329783
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606893}
1 file changed