downgrade log of util.ExecuteCommand

As this error E0531 is not that ueful and no need to be mark
this as 'E', use Info level should be fine as this won't affect
return value.

pkg/util/util.go

@@ -161,13 +161,14 @@ func Copy(m *clusterv1.Machine) *clusterv1.Machine {
 }
 
 // ExecCommand Executes a local command in the current shell.
-func ExecCommand(name string, args ...string) string {
+func ExecCommand(name string, args ...string) (string, error) {
 	cmdOut, err := exec.Command(name, args...).Output()
 	if err != nil {
 		s := strings.Join(append([]string{name}, args...), " ")
-		klog.Errorf("error executing command %q: %v", s, err)
+		klog.Infof("Executing command %q: %v", s, err)
+		return string(""), err
 	}
-	return string(cmdOut)
+	return string(cmdOut), nil
 }
 
 // Filter filters a list for a string.