makefile: remove gliderlabs/glu ci build dependency

Makefile

@@ -19,15 +19,15 @@ release:
 	cp build/* release
 	gh-release create gliderlabs/$(NAME) $(VERSION) \
 		$(shell git rev-parse --abbrev-ref HEAD) $(VERSION)
-	glu hubtag gliderlabs/$(NAME) $(VERSION)
 
 docs:
 	boot2docker ssh "sync; sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'" || true
 	docker run --rm -it -p 8000:8000 -v $(PWD):/work gliderlabs/pagebuilder mkdocs serve
 
 circleci:
-	rm -f ~/.gitconfig
-	go get -u github.com/gliderlabs/glu
-	glu circleci
+	rm ~/.gitconfig
+ifneq ($(CIRCLE_BRANCH), release)
+	echo build-$$CIRCLE_BUILD_NUM > VERSION
+endif
 
 .PHONY: build release docs