Update to the rustfmt in rust 1.31, which is now stable.

lib/filetests/src/concurrent.rs

@@ -106,7 +106,8 @@ fn heartbeat_thread(replies: Sender<Reply>) -> thread::JoinHandle<()> {
             while replies.send(Reply::Tick).is_ok() {
                 thread::sleep(Duration::from_secs(1));
             }
-        }).unwrap()
+        })
+        .unwrap()
 }
 
 /// Spawn a worker thread running tests.
@@ -153,5 +154,6 @@ fn worker_thread(
             // Timing is accumulated independently per thread.
             // Timings from this worker thread will be aggregated by `ConcurrentRunner::join()`.
             timing::take_current()
-        }).unwrap()
+        })
+        .unwrap()
 }