Use a symbolic name for the RUST_LOG level
Use a symbolic name for the RUST_LOG level

edunham/rust-buildbot,edunham/rust-buildbot,rust-lang-deprecated/rust-buildbot,edunham/rust-buildbot,rust-lang-deprecated/rust-buildbot,rust-lang-deprecated/rust-buildbot,aidanhs/rust-buildbot,rust-lang/rust-buildbot,aidanhs/rust-buildbot,rust-lang/rust-buildbot,rust-lang/rust-buildbot,aidanhs/rust-buildbot