Simplify the Travis-CI configuration.
Simplify the Travis-CI configuration.

Even though Travis does NOT offer a consistent Go platform, I want
to nevertheless simplify the scaffolding scripts around it to make
it easier for other folks to perform pull requests, reviews, etc.
while letting the tests run.

telendt/client_golang,jimmidyson/prometheus-client_golang,fabxc/client_golang,stapelberg/client_golang,prometheus/client_golang,asbjornenge/client_golang,KevinPike/client_golang,mattkanwisher/client_golang,m3db/prometheus_client_golang