Make a test compatible with the beta channel

Author: brson

src/test/compile-fail/gated-associated_consts.rs

@@ -11,13 +11,11 @@
 trait MyTrait {
     const C: bool;
     //~^ associated constants are experimental
-    //~| add #![feature(associated_consts)] to the crate attributes to enable
 }
 
 struct Foo;
 
 impl Foo {
     const C: bool = true;
     //~^ associated constants are experimental
-    //~| add #![feature(associated_consts)] to the crate attributes to enable
 }