waitPidStop: simplify code

The code can be simplified by using a timer directly.

[NO NEW TESTS NEEDED] - should not change behavior.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

libpod/oci_conmon_common.go

@@ -949,32 +949,21 @@ func waitContainerStop(ctr *Container, timeout time.Duration) error {
 
 // Wait for a given PID to stop
 func waitPidStop(pid int, timeout time.Duration) error {
-	done := make(chan struct{})
-	chControl := make(chan struct{})
-	go func() {
+	timer := time.NewTimer(timeout)
 	for {
 		select {
-			case <-chControl:
-				return
+		case <-timer.C:
+			return fmt.Errorf("given PID did not die within timeout")
 		default:
 			if err := unix.Kill(pid, 0); err != nil {
 				if err == unix.ESRCH {
-						close(done)
-						return
+					return nil
 				}
 				logrus.Errorf("Pinging PID %d with signal 0: %v", pid, err)
 			}
 			time.Sleep(100 * time.Millisecond)
 		}
 	}
-	}()
-	select {
-	case <-done:
-		return nil
-	case <-time.After(timeout):
-		close(chControl)
-		return fmt.Errorf("given PIDs did not die within timeout")
-	}
 }
 
 func (r *ConmonOCIRuntime) getLogTag(ctr *Container) (string, error) {