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

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

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I6a0b029465405473263b83f81dab1b484df7a3a8