Merge "ueventd: Fix a race condition in handling device-mapper events." into udc-dev am: c742bfda6b

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/23598091

Change-Id: I22b5bb96a54c91ab124377a69ee53616c6eba018
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>