Migrate to cargo_embargo. am: ba08b5b7c3 am: a0306c11be

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/vhost-user-backend/+/2824632

Change-Id: I4aa24b7e65333de554447acf6eea70f21bbb5cdf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>