Add unnecessary vendor `lint` after `make check`

[overvenus]

After including _vendor/src to GOPATH, we may add unnecessary vendor lint after make check if there is no lint present.

neil:tidb/ (master*) $ gst                                                                                                             [12:21:18]
On branch master
Your branch is up-to-date with 'upstream/master'.

Untracked files:
  (use "git add <file>..." to include in what will be committed)

    _vendor/pkg/
    _vendor/src/github.com/golang/lint/

no changes added to commit (use "git add" and/or "git commit -a")

ref: #1748

/cc: @tiancaiamao

[overvenus]

I think .gitignore is the quickest solution.

[overvenus]

make install may fails too.

[tiancaiamao]

let go get github.com/golang/lint/golint use the origin GOPATH ?
@shenli

[tiancaiamao]

make install can be removed, I think

[tiancaiamao]

and @coocood , what's your option?

[coocood]

go get golint use origin GOPATH is better.

[overvenus]

Not only golint. Glide, errcheck and anything relate to go (get|build|install) may be affected.

[overvenus]

close via #1782