Rm unused feature

Manishearth · Manishearth · commit 6f930b99b0db · 2015-03-19T08:49:39.000+05:30
diff --git a/src/compiletest/compiletest.rs b/src/compiletest/compiletest.rs
@@ -19,7 +19,6 @@
 #![feature(unboxed_closures)]
 #![feature(std_misc)]
 #![feature(test)]
-#![feature(core)]
 #![feature(path_ext)]
 
 #![deny(warnings)]
