Bug#1076477: rust-async-channel - unsatisfiable test dependency.

[Peter Michael Green]

Package: rust-async-channel
Version: 2.3.1-4

One of the tests for rust-async-channel depends on 
|librust-easy-parallel-3+std-dev
which does not exist. This is blocking migration to testing.
After looking at the Cargo.toml files I belive this should be changed to |
||librust-easy-parallel-3+default-dev||