Remove libtest from deps

Author: Manishearth

Cargo.toml

@@ -48,7 +48,6 @@ rustc_tools_util = { version = "0.1.1", path = "rustc_tools_util"}
 clippy_dev = { version = "0.0.1", path = "clippy_dev" }
 cargo_metadata = "0.7.1"
 compiletest_rs = { version = "0.3.21" }
-libtest = "0.0.1"
 lazy_static = "1.0"
 serde_derive = "1.0"
 clippy-mini-macro-test = { version = "0.2", path = "mini-macro" }