Merge "remount: Remove errno test & improve messaging of fs_mgr_overlayfs_mount_all" am: 7214c98d2e

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2228578

Change-Id: I36109eedbf286f35b36373845a60c89f54da2880
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>