Revert "Use rustc instead of clippy."

This reverts commit ef306a7f9e.

travis-cargo doesn't support --lib or --bin so we can't do this anyway.

.travis.yml

@@ -8,15 +8,15 @@ before_script:
     - pip install 'travis-cargo>=0.1.0,<0.2.0' --user
     - pip install 'CppHeaderParser>=2.7.2,<3.0.0' --user
     - export PATH="$HOME/.local/bin:$PATH"
-    - git clone https://github.com/Manishearth/clippy.git
-    - cd clippy
+    - git clone https://github.com/arcnmx/cargo-clippy.git
+    - cd cargo-clippy
     - travis-cargo --only nightly build
-    - export CLIPPY_PATH="$PWD/target/debug"
+    - export PATH="$PWD/target/debug:$PATH"
     - cd ..
 script:
     - travis-cargo build
-    - travis-cargo --only nightly rustc --lib -- -L "$CLIPPY_PATH" -l clippy -Z extra-plugins=clippy -Z no-trans
-    - travis-cargo --only nightly rustc --bin cheddar -- -L "$CLIPPY_PATH" -l clippy -Z extra-plugins=clippy -Z no-trans
+    - ./on-nightly cargo clippy --lib
+    - ./on-nightly cargo clippy --bin cheddar
     - travis-cargo test
     - travis-cargo --only stable doc
 after_success:

on-nightly

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+if [[ "$TRAVIS_RUST_VERSION" = 'nightly' ]]
+then
+    $@
+fi