Merge "Crash happens if back button is pressed during "Format as Portable""...

Merge "Crash happens if back button is pressed during "Format as Portable"" am: 671fa153 am: 6945e70c

Original change: https://android-review.googlesource.com/c/platform/packages/apps/Settings/+/2147940



Change-Id: Ib4fcff818a81a38c08f31d552706fc567ec00daa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>