Fix mac osx installation issue

[ghost]

• Fixes Installation issue when using homebrew python on Mac OSX #513
• Address partially ydk installation issues on some CentOS environments #518

[codecov]

Codecov Report

Merging #610 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #610   +/-   ##
=======================================
  Coverage   73.28%   73.28%           
=======================================
  Files         104      104           
  Lines       10346    10346           
  Branches     1448     1448           
=======================================
  Hits         7582     7582           
  Misses       2487     2487           
  Partials      277      277

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[codecov]

Codecov Report

Merging #610 into master will increase coverage by <.01%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master     #610      +/-   ##
==========================================
+ Coverage   73.28%   73.28%   +<.01%     
==========================================
  Files         104      104              
  Lines       10346    10347       +1     
  Branches     1448     1448              
==========================================
+ Hits         7582     7583       +1     
  Misses       2487     2487              
  Partials      277      277

Impacted Files	Coverage Δ
...en/printer/go/generated_package_methods_printer.py	23.52% <0%> (ø)	⬆️
ydkgen/printer/go/class_constructor_printer.py	14.46% <100%> (+0.36%)	⬆️

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