fix issue #207: common/utils/net_test.go:25 cannot pass

[beiwei30]

What this PR does:

Which issue(s) this PR fixes:

Fixes #207

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-io]

Codecov Report

Merging #209 into develop will increase coverage by <.01%.
The diff coverage is 63.88%.

@@             Coverage Diff             @@
##           develop     #209      +/-   ##
===========================================
+ Coverage    65.28%   65.28%   +<.01%     
===========================================
  Files           96       96              
  Lines         6444     6462      +18     
===========================================
+ Hits          4207     4219      +12     
- Misses        1798     1801       +3     
- Partials       439      442       +3

Impacted Files	Coverage Δ
common/utils/net.go	62% <63.88%> (-9.88%)	⬇️
remoting/zookeeper/client.go	64.45% <0%> (+0.57%)	⬆️
remoting/zookeeper/listener.go	47.93% <0%> (+1.03%)	⬆️

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[wongoo]

LGTM