librustc_trans: fix fallout

Author: Jorge Aparicio

src/librustc_trans/back/link.rs

@@ -1002,7 +1002,7 @@ fn link_args(cmd: &mut Command,
     if sess.opts.cg.rpath {
         let sysroot = sess.sysroot();
         let target_triple = sess.opts.target_triple.as_slice();
-        let get_install_prefix_lib_path = || {
+        let get_install_prefix_lib_path = |:| {
             let install_prefix = option_env!("CFG_PREFIX").expect("CFG_PREFIX");
             let tlib = filesearch::relative_target_lib_path(sysroot, target_triple);
             let mut path = Path::new(install_prefix);