Fix noVNC git repo

Recent change switched base git URL to git.openstack.org.
However, noVNC is only hosted on GitHub.
Change git repo URL for noVNC back to the GitHub one.

Change-Id: Iaa9f570639301be1c29cc400c1c73afcbf637b70
diff --git a/stackrc b/stackrc
index 7eda5a5..410f9d8 100644
--- a/stackrc
+++ b/stackrc
@@ -178,7 +178,7 @@
 BM_POSEUR_BRANCH=${BM_POSEUR_BRANCH:-master}
 
 # a websockets/html5 or flash powered VNC console for vm instances
-NOVNC_REPO=${NOVNC_REPO:-${GIT_BASE}/kanaka/noVNC.git}
+NOVNC_REPO=${NOVNC_REPO:-https://github.com/kanaka/noVNC.git}
 NOVNC_BRANCH=${NOVNC_BRANCH:-master}
 
 # ryu service