update .travis.yml with new golint path

.travis.yml

@@ -1,14 +1,13 @@
 language: go
 go:
-- 1.8
-- 1.9
+- 1.11.x
 - tip
 before_install:
-- go get -v github.com/golang/lint/golint
+- go get -v golang.org/x/lint/golint
 script:
 - $HOME/gopath/bin/golint -min_confidence 0.9 -set_exit_status
 - GORACE="exitcode=1 halt_on_error=1" go test -v -coverprofile=coverage.txt -race -timeout 3m -count 3 -cpu 1,4
-- go tool vet -v -all .
+- go vet -v .
 after_success:
   - bash <(curl -s https://codecov.io/bash)
 branches: