travis: remove lint from travis

Author: haya14busa

.travis.yml

@@ -16,11 +16,5 @@ before_script:
 script:
   - go test -v -race ./...
   - goveralls -service=travis-ci
-  - go vet ./...
-  - golint -set_exit_status .
-  - golint -set_exit_status ./token
-  - golint -set_exit_status ./compiler
-  - golint ./ast
-  - unused ./...
   - vim -u NONE -N --cmd "let &rtp .= ',' . getcwd()" -S go/generate.vim -c ":q"
   - (! git diff | grep '^') # check diff