Merge "Bail out properly when we can't find a keymaster instance." am: 5728c7d121

Original change: https://android-review.googlesource.com/c/platform/system/security/+/1607115

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I77f1185ed2b5889983aa6d3f8de12b5e313a48e0