Add regression test for lint deprecation

Author: aturon

src/test/compile-fail/lint-renaming.rs

@@ -0,0 +1,16 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Check that lint deprecation works
+
+#[deny(unused_variable)] //~ warning: lint unused_variable has been renamed to unused_variables
+pub fn main() {
+    let x = 0u8; //~ error: unused variable:
+}