rustc: Fix parsing of `ret &EXPR`

The parser didn't think that `&` could start an expression.

src/rustc/syntax/parse/token.rs

@@ -186,6 +186,7 @@ pure fn can_begin_expr(t: token) -> bool {
       NOT { true }
       BINOP(MINUS) { true }
       BINOP(STAR) { true }
+      BINOP(AND) { true }
       MOD_SEP { true }
       _ { false }
     }