golint:normalize some codes

[Tronegacy]

amend seven places' codes all is warning with redundant if at the end of servel “if ...; err != nil”.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)? (你真的觉得不需要加测试吗？)

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

Merging #2308 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2308      +/-   ##
==========================================
+ Coverage   66.97%   67.03%   +0.05%     
==========================================
  Files         211      211              
  Lines       17306    17292      -14     
==========================================
  Hits        11591    11591              
+ Misses       4312     4304       -8     
+ Partials     1403     1397       -6

Flag	Coverage Δ
#criv1alpha1test	32.33% <57.14%> (+0.25%)	⬆️
#criv1alpha2test	35.75% <71.42%> (+0.15%)	⬆️
#integrationtest	40.25% <100%> (+0.07%)	⬆️
#nodee2etest	33.02% <57.14%> (-0.11%)	⬇️
#unittest	23.42% <28.57%> (+0.02%)	⬆️

Impacted Files	Coverage Δ
storage/volume/core.go	67.14% <100%> (+0.63%)	⬆️
pkg/archive/archive.go	53.84% <100%> (+1.99%)	⬆️
daemon/mgr/spec_process.go	67.01% <100%> (+1.35%)	⬆️
daemon/mgr/container_validation.go	45.69% <100%> (+0.59%)	⬆️
daemon/mgr/spec_linux.go	75.37% <100%> (+0.9%)	⬆️
daemon/mgr/spec.go	61.9% <100%> (-3.32%)	⬇️
cri/ocicni/cni_manager.go	65% <0%> (-15%)	⬇️
cri/v1alpha2/cri_wrapper.go	61.2% <0%> (-1.2%)	⬇️
cri/v1alpha2/cri.go	65.45% <0%> (-0.88%)	⬇️
cri/v1alpha2/cri_utils.go	90.28% <0%> (-0.29%)	⬇️
... and 7 more

[pouchrobot]

We found this is your first time to contribute to Pouch, @Tronegacy
👏 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]

All committers have signed the CLA.

[pouchrobot]

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

[HusterWan]

LGTM

[HusterWan]

@Tronegacy Please suqash your commits, thanks a lot

[HusterWan]

@Tronegacy Please suqash your commits, thanks a lot

since the github can do squash action when merge PR, so i merged this PR