Imp: modify codes by code review of gitee

[georgehao]

What this PR does:

1. modify part of code style

Which issue(s) this PR fixes:

Fixes #514

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #590 into develop will decrease coverage by 0.04%.
The diff coverage is 59.09%.

@@             Coverage Diff             @@
##           develop     #590      +/-   ##
===========================================
- Coverage    67.39%   67.35%   -0.05%     
===========================================
  Files          188      188              
  Lines         9849     9852       +3     
===========================================
- Hits          6638     6636       -2     
- Misses        2560     2565       +5     
  Partials       651      651              

Impacted Files	Coverage Δ
cluster/cluster_impl/forking_cluster_invoker.go	58.33% <0.00%> (-0.21%)	⬇️
common/extension/config_center.go	0.00% <0.00%> (ø)
cluster/cluster_impl/base_cluster_invoker.go	61.11% <66.66%> (-11.36%)	⬇️
cluster/cluster_impl/failover_cluster_invoker.go	71.15% <68.75%> (-1.19%)	⬇️
config_center/nacos/facade.go	81.25% <0.00%> (-9.38%)	⬇️
cluster/directory/base_directory.go	56.81% <0.00%> (-9.10%)	⬇️
registry/kubernetes/registry.go	57.69% <0.00%> (-5.77%)	⬇️
remoting/kubernetes/client.go	76.25% <0.00%> (-2.50%)	⬇️
remoting/kubernetes/watch.go	78.89% <0.00%> (-1.84%)	⬇️
... and 6 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 4dac621...158ff81. Read the comment docs.

[fangyincheng]

LGTM

[hxmhlt]

LGTM