fix vet make target to vet all packages

The vet target was only vetting the topmmost packages.

Makefile

@@ -1,5 +1,4 @@
 TEST?=$$(go list ./... | grep -v '/terraform/vendor/' | grep -v '/builtin/bins/')
-VETARGS?=-all
 GOFMT_FILES?=$$(find . -name '*.go' | grep -v vendor)
 
 default: test vet
@@ -74,8 +73,8 @@ cover:
 # vet runs the Go source code static analysis tool `vet` to find
 # any common errors.
 vet:
-	@echo "go tool vet $(VETARGS) ."
-	@go tool vet $(VETARGS) $$(ls -d */ | grep -v vendor) ; if [ $$? -eq 1 ]; then \
+	@echo "go vet ."
+	@go vet $$(go list ./... | grep -v vendor/) ; if [ $$? -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."; \