Fix: chaosfs pseudo random errno UT

[Gallardot]

What problem does this PR solve?

randomErrno is pseudo random function. It could be the same thing both times. Sometimes jenkins may report an error.

What is changed and how does it work?

Check List

Tests

• Unit test

Code changes

• Has Go code change

Side effects

• None

Related changes

• None

Does this PR introduce a user-facing change?:

NONE

[codecov-io]

Codecov Report

Merging #398 into master will decrease coverage by 2.26%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #398      +/-   ##
==========================================
- Coverage   60.87%   58.60%   -2.27%     
==========================================
  Files          61       60       -1     
  Lines        3798     3624     -174     
==========================================
- Hits         2312     2124     -188     
- Misses       1326     1331       +5     
- Partials      160      169       +9     

Impacted Files	Coverage Δ
api/v1alpha1/iochaos_webhook.go	77.41% <0.00%> (-15.69%)	⬇️
api/v1alpha1/networkchaos_webhook.go	82.05% <0.00%> (-14.83%)	⬇️
api/v1alpha1/timechaos_webhook.go	77.41% <0.00%> (-11.77%)	⬇️
api/v1alpha1/kernelchaos_webhook.go	77.41% <0.00%> (-7.77%)	⬇️
api/v1alpha1/timechaos_types.go	4.34% <0.00%> (-6.07%)	⬇️
api/v1alpha1/podchaos_webhook.go	81.25% <0.00%> (-3.50%)	⬇️
pkg/utils/selector.go	51.65% <0.00%> (-0.83%)	⬇️
api/v1alpha1/iochaos_types.go	32.55% <0.00%> (ø)
api/v1alpha1/common_webhook.go	100.00% <0.00%> (ø)
api/v1alpha1/podchaos_types.go	32.55% <0.00%> (ø)
... and 3 more

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[cwen0]

LGTM

[zhouqiang-cl]

LGTM

[zhouqiang-cl]

/merge

[sre-bot]

/run-all-tests