Added failint to make lint

Fixes thanos-io#2142

Makefile

@@ -296,7 +296,7 @@ failint:
 #      --mem-profile-path string   Path to memory profile output file
 #
 # to debug big allocations during linting.
-lint: check-git $(GOLANGCILINT) $(MISSPELL)
+lint: check-git $(GOLANGCILINT) $(MISSPELL) failint
 	@echo ">> examining all of the Go files"
 	@go vet -stdmethods=false ./pkg/... ./cmd/... && go vet doc.go
 	@echo ">> linting all of the Go files GOGC=${GOGC}"
@@ -309,7 +309,7 @@ lint: check-git $(GOLANGCILINT) $(MISSPELL)
 	@echo ">> ensuring Copyright headers"
 	@go run ./scripts/copyright
 	$(call require_clean_work_tree,"detected files without copyright")
-	failint
+
 
 .PHONY: web-serve
 web-serve: web-pre-process $(HUGO)