Merge pull request kubernetes#61624 from jianglingxia/selinux2018032412

Automatic merge from submit-queue (batch tested with PRs 61644, 61624, 61743, 61019, 61287). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Add a sceneo UT test to TestMustRunAsOptions

**What this PR does / why we need it**:
Add a sceneo UT test to TestMustRunAsOptions when the opts is nil
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

Author: Kubernetes Submit Queue

pkg/security/podsecuritypolicy/selinux/mustrunas_test.go

@@ -29,6 +29,10 @@ func TestMustRunAsOptions(t *testing.T) {
 		opts *extensions.SELinuxStrategyOptions
 		pass bool
 	}{
+		"nil opts": {
+			opts: nil,
+			pass: false,
+		},
 		"invalid opts": {
 			opts: &extensions.SELinuxStrategyOptions{},
 			pass: false,