e2e_node: remove Dbus test case

The test case restarts dbus and systemd, which is considered dangerous
practice and caused slowdown of the test cases for CRI-O Serial jobs.

test/e2e_node/node_shutdown_linux_test.go

@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"regexp"
 	"strconv"
 	"time"
@@ -652,44 +651,6 @@ func getNodeReadyStatus(ctx context.Context, f *framework.Framework) bool {
 	return isNodeReady(&nodeList.Items[0])
 }
 
-func systemctlDaemonReload() error {
-	cmd := "systemctl daemon-reload"
-	_, err := runCommand("sh", "-c", cmd)
-	return err
-}
-
-var (
-	dbusConfPath = "/etc/systemd/system/dbus.service.d/k8s-graceful-node-shutdown-e2e.conf"
-	dbusConf     = `
-[Unit]
-RefuseManualStart=no
-RefuseManualStop=no
-[Service]
-KillMode=control-group
-ExecStop=
-`
-)
-
-func overlayDbusConfig() error {
-	err := os.MkdirAll(filepath.Dir(dbusConfPath), 0755)
-	if err != nil {
-		return err
-	}
-	err = os.WriteFile(dbusConfPath, []byte(dbusConf), 0644)
-	if err != nil {
-		return err
-	}
-	return systemctlDaemonReload()
-}
-
-func restoreDbusConfig() error {
-	err := os.Remove(dbusConfPath)
-	if err != nil {
-		return err
-	}
-	return systemctlDaemonReload()
-}
-
 const (
 	// https://github.com/kubernetes/kubernetes/blob/1dd781ddcad454cc381806fbc6bd5eba8fa368d7/pkg/kubelet/nodeshutdown/nodeshutdown_manager_linux.go#L43-L44
 	podShutdownReason  = "Terminated"