Travis: do not fetch modules during CI (#677)

Makefile

@@ -20,7 +20,7 @@ setup-dev-env:
 verify:
 	./scripts/check_gofmt.sh
 	./scripts/check_golint.sh
-	./scripts/check_deps.sh
+	# ./scripts/check_deps.sh TODO: comment back when we stop using vendor.
 	./scripts/check_conflicts.sh
 
 .PHONY: test

scripts/check_golint.sh

@@ -4,4 +4,4 @@
 # Run the linter on everything except generated code
 set -euo pipefail
 
-golint -set_exit_status $(go list ./... | grep -v '/mocks')
+GO111MODULE=off golint -set_exit_status $(go list ./... | grep -v '/mocks')