Cleanup license metadata in external/rust/crates/futures-macro. am: 97e35ba490

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-macro/+/3205742

Change-Id: I87ecafcfd72c8790b739cfd77dfaeba16ee3539e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>