#785 add command unit test

[caugello]

What this PR does / why we need it:

Unit test for maya-apiserver cmd. (commands.go)

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Fixes: openebs/785

Special notes for your reviewer:

[codecov]

Codecov Report

Merging #253 into master will increase coverage by 0.85%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #253      +/-   ##
==========================================
+ Coverage   26.26%   27.11%   +0.85%     
==========================================
  Files          43       43              
  Lines        3739     3739              
==========================================
+ Hits          982     1014      +32     
+ Misses       2644     2610      -34     
- Partials      113      115       +2

Impacted Files	Coverage Δ
cmd/maya-apiserver/app/command/start.go	9.84% <0%> (+9.84%)	⬆️
cmd/maya-apiserver/app/command/version.go	50% <0%> (+50%)	⬆️
cmd/maya-apiserver/app/command/commands.go	100% <0%> (+100%)	⬆️

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[kmova]

Thank you @kartouch

[nitisuryawanshi]

@kartouch thank you for your contribution to OpenEBS. We would like to send you some OpenEBS Swag as a thank you note from the OpenEBS team. Will you please fill out this form with your details so that we start processing it ASAP? https://cloudbyte.agilecrm.com/forms/5126296610799616