Make pre-commit more portable and less tricky.

.travis.yml

@@ -26,19 +26,12 @@ go_import_path: sigs.k8s.io/kustomize
 
 before_install:
   - source ./travis/consider-early-travis-exit.sh
-  - curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $(go env GOPATH)/bin v1.17.1
-  - GO111MODULE=on go get sigs.k8s.io/kustomize/pluginator@v1
-  - go get -u github.com/monopole/mdrip
-  # The following would install Helm if needed for some reason.
-  # - wget https://storage.googleapis.com/kubernetes-helm/helm-v2.13.1-linux-amd64.tar.gz
-  # - tar -xvzf helm-v2.13.1-linux-amd64.tar.gz
-  # - sudo mv linux-amd64/helm /usr/local/bin/helm
 
 # Skip the install process; let pre-commit.sh do it.
 install: true
 
 script:
-  - env GO111MODULE=on ./travis/pre-commit.sh
+  - ./travis/pre-commit.sh
 
 # TBD. Suppressing for now.
 notifications: