Categorize the unwrap lints correctly.

clippy_lints/src/lib.rs

@@ -926,6 +926,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
         mutex_atomic::MUTEX_INTEGER,
         needless_borrow::NEEDLESS_BORROW,
         ranges::RANGE_PLUS_ONE,
+        unwrap::PANICKING_UNWRAP,
         unwrap::UNNECESSARY_UNWRAP,
     ]);
 }