unxfail test for #2657

Author: nikomatsakis

src/test/compile-fail/borrowck-issue-2657-2.rs

@@ -1,13 +1,8 @@
-//xfail-test
-
-// this should be illegal but borrowck is not handling 
-// pattern bindings correctly right now
-
 fn main() {
 let x = some(~1);
 alt x {
   some(y) {
-    let b <- y;
+    let _b <- y; //! ERROR moving out of pattern binding
   }
   _ {}
 }