Fix futures-channel/METADATA am: 5dedceab5a am: 49babae9ee am: dc28ec101c am: 70f7120dc2 am: 8e7c2c6b2e

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-channel/+/1414035

Change-Id: Ia215f0725015fd8acaf4cb929dcf0acd4185ecf7