Add timeout while waiting for StartTransinetUnit completion signal from dbus

Author: vikaschoudhary16

libcontainer/cgroups/systemd/apply_systemd.go

@@ -300,7 +300,10 @@ func (m *Manager) Apply(pid int) error {
 		return err
 	}
 
-	<-statusChan
+	select {
+	case <-statusChan:
+	case <-time.After(time.Second):
+	}
 
 	if err := joinCgroups(c, pid); err != nil {
 		return err