golint is not respected in ci

[cappyzawa]

Background

• golint is not respected in travis ci.
  • After running golint, even if there are problems exit code is 0.
  • Only files under project's root are considered in the golint . command
• I fixed based on golint and executed gofmt (a53fb5f)
  • before: Build #832 - tsenart/vegeta - Travis CI
  • After: Build #833 - tsenart/vegeta - Travis CI

Checklist

• Git commit messages conform to community standards.
• Each Git commit represents meaningful milestones or atomic units of work.
• Changed or added code is covered by appropriate tests.

[tsenart]

Looks good to me, thanks!