266-7:add unit-test for getSELinuxSecurityOpts #1912

[sushengl]

Ⅰ. Describe what this PR did

add a unit-test for method getSELinuxSecurityOpts in cri_utils.go

Ⅱ. Does this pull request fix one issue?

fix issues #1912

Ⅲ. Describe how you did it

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[pouchrobot]

We found this is your first time to contribute to Pouch, @sushengl
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[pouchrobot]

@sushengl Thanks for your contribution. 🍻
Please sign off in each of your commits.

[pouchrobot]

ping @sushengl
We found that this PR is 22 commits, which is more than 10 commits, behind master.
Please rebase the branch against master and push it back again. Thanks a lot.