add drop so test does not hang

Author: rapha

src/libstd/sync/mpsc/mod.rs

@@ -907,7 +907,7 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn next(&mut self) -> Option<T> { self.rx.recv().ok() }
 }
 
-#[stable(feature = "receiver_into_iter", since = "1.1.0")]
+#[stable(feature = "rust1_1", since = "1.1.0")]
 impl<'a, T> IntoIterator for &'a Receiver<T> {
     type Item = T;
     type IntoIter = Iter<'a, T>;
@@ -1557,6 +1557,7 @@ mod test {
         let (tx, rx) = channel::<i32>();
         tx.send(1).unwrap();
         tx.send(2).unwrap();
+        drop(tx);
         let mut iter = (&rx).into_iter();
         assert_eq!(iter.next().unwrap(), 1);
         assert_eq!(iter.next().unwrap(), 2);