ref(*): Manage test dependencies using godeps

Simplify test running and dependency management.

Follow deis coding standards
> Use of third-party go packages should be minimal, but when doing so,
vendor code into the Deis package with the godep tool.

Author: johanneswuerbach

Makefile

@@ -72,4 +72,4 @@ test-unit: setup-venv test-style
 test-functional:
 	@docker history deis/test-etcd >/dev/null 2>&1 || docker pull deis/test-etcd:latest
 	@docker history deis/test-postgresql >/dev/null 2>&1 || docker pull deis/test-postgresql:latest
-	GOPATH=$(CURDIR)/../tests/_vendor:$(GOPATH) go test -v ./tests/...
+	GOPATH=`cd ../tests/ && godep path`:$(GOPATH) go test -v ./tests/...