Adding voltctl page downloading the README from opencord/voltctl

Change-Id: I3ed6218273c65498cb704d3048c38b49c2321da8
diff --git a/git_refs b/git_refs
index 1aba496..8fa142d 100644
--- a/git_refs
+++ b/git_refs
@@ -18,3 +18,4 @@
 voltha-openonu-adapter  /        master
 voltha-protos           /        master
 voltha-system-tests     /        master
+voltctl                 /        master