Fix vet to exclude scripts directory

- Exclude scripts directory from go vet checks
- Scripts are standalone executables and shouldn't be checked together
- Fixes 'main redeclared' error when both test-runner.go and make-release.go exist

Author: zph

Makefile

@@ -182,7 +182,7 @@ testmariadb: ## Run tests against MariaDB version (set MYSQL_VERSION)
 
 vet: ## Run go vet
 	@echo "go vet ."
-	@go vet $$(go list ./... | grep -v vendor/) ; if [ $$? -eq 1 ]; then \
+	@go vet $$(go list ./... | grep -v vendor/ | grep -v '/scripts') ; if [ $$? -eq 1 ]; then \
 		echo ""; \
 		echo "Vet found suspicious constructs. Please check the reported constructs"; \
 		echo "and fix them if necessary before submitting the code for review."; \