Merge "fs_mgr_overlayfs: Don't try to mount scratch if already mounted" into...

Merge "fs_mgr_overlayfs: Don't try to mount scratch if already mounted" into main am: 7bcd7715 am: ad6295b4

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2797335



Change-Id: Iaa383e0d6ada408c492e51e58b8d6a728103a7f1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>