Merge "mkdir .incomplete in backing storage to fix CTS/GTS failures" am: cb5c02da8b am: e8aad7ca43 am: fe071a9d5f

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1536324

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ib4954d3ee1fdcf7814c7bedc1ba4852356354afc