Merge "ueventd: Fix a race condition in handling device-mapper events." into udc-dev am: c742bfda

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



Change-Id: Id7f61666c8886a08d2fa12be10015be307f79661
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>