Stub Makefile to call Makefile in python subdir

add `test` target that checks that the container builds

Change-Id: I37277d75e6797107b1df106ea1eb744c67897bb9
diff --git a/python/Makefile b/python/Makefile
index 79514eb..2a86247 100644
--- a/python/Makefile
+++ b/python/Makefile
@@ -58,7 +58,10 @@
 
 build: docker-build
 
-local-protos: 
+# only test is that the docker container builds
+test: docker-build
+
+local-protos:
 	mkdir -p local_imports
 ifdef LOCAL_PROTOS
 	mkdir -p local_imports/voltha-protos/dist