message: Switch to using the official cargo clippy for CI.
diff: set -ex
  if [ "$TRAVIS_RUST_VERSION" = "nightly" ]; then
  - oldpath=$(pwd)
  - cd $HOME
  - git clone https://github.com/arcnmx/cargo-clippy
  - cd $HOME/cargo-clippy
  - cargo build --release
  - cd $oldpath
  + cargo install clippy
  fi
  