add support for unix domain sockets

[flokli]

grpc.NewClient already supports connecting to unix domain sockets, and accepts a string anyways.

As a quick fix, detect the address starting with unix:// and don't add the port.

In the long term, we might want to deprecate host and port cmdline args in favor of a single address arg.

Fixes #654.

[codecov[bot]]

Codecov Report

Merging #680 (55d7e7a) into master (d1bc03a) will increase coverage by 0.02%. The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #680      +/-   ##
==========================================
+ Coverage   77.10%   77.13%   +0.02%     
==========================================
  Files          57       57              
  Lines        3910     3915       +5     
==========================================
+ Hits         3015     3020       +5     
  Misses        647      647              
  Partials      248      248              

[flokli]

@ktr0731 poke ;-)