Update requirements to newer voltha-protos

Also remove circular dependency

Change-Id: I633df5fccf2cf36b690a1d30f49394a4fc640eb8
diff --git a/requirements.txt b/requirements.txt
index 874a801..c8659a7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -60,5 +60,4 @@
 pexpect==4.6.0
 python-consul==0.6.2
 afkak==3.0.0.dev20181106
-pyvoltha==0.1.8
-voltha-protos==0.1.2
+voltha-protos==0.1.4