fix TestDaemonRestartWithInvalidBasesize

NotNil is expected behaviour, daemon should not start with
invalid base size.

Signed-off-by: Fengtu Wang <wangfengtu@huawei.com>

integration-cli/docker_cli_daemon_test.go

@@ -198,7 +198,12 @@ func (s *DockerDaemonSuite) TestDaemonRestartWithInvalidBasesize(c *check.C) {
 
 	if newBasesizeBytes < oldBasesizeBytes {
 		err := s.d.RestartWithError("--storage-opt", fmt.Sprintf("dm.basesize=%d", newBasesizeBytes))
-		c.Assert(err, check.IsNil, check.Commentf("daemon should not have started as new base device size is less than existing base device size: %v", err))
+		c.Assert(err, check.NotNil, check.Commentf("daemon should not have started as new base device size is less than existing base device size: %v", err))
+		// 'err != nil' is expected behaviour, no new daemon started,
+		// so no need to stop daemon.
+		if err != nil {
+			return
+		}
 	}
 	s.d.Stop(c)
 }