Merge "first_stage_mount: Bind mount /system after switch root" am: 53f1fab6...

Merge "first_stage_mount: Bind mount /system after switch root" am: 53f1fab6 am: c3e43e63 am: e3976090

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2146960



Change-Id: Ied075867ced373f0a07a155176d0013b60cd5d44
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>