[VOL-936] add changes for onu distance proto

Change-Id: Iedc44ff0c1c26a7d3623d4b7d96bb2d425d5d24f
diff --git a/Makefile b/Makefile
index 7da9db9..fc97114 100644
--- a/Makefile
+++ b/Makefile
@@ -67,7 +67,7 @@
 python-protos: $(PROTO_PYTHON_PB2)
 
 venv_protos:
-	virtualenv $@;\
+	virtualenv -p python3 $@;\
 	source ./$@/bin/activate ; set -u ;\
 	pip install grpcio-tools googleapis-common-protos