Migrate to cargo_embargo. am: 3e1c42f469 am: bbe624c5a7

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/fnv/+/2796414

Change-Id: I43215fda83e4b590d7a90f61509c004335b38cec
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>