Configures novnc proxy to listen on local-ipv4

Currently novnc proxy listens on all interfaces. This patch changes
it to listen on the host management interface (local-ipv4) like the
rest of the nova services. This is a pre-requisite to making vncproxy
sit behind haproxy and stunnel.

Change-Id: Iba3e35165a1e842ce0fc604ec92ddbd0009e99c2
Merge "Configures novnc proxy to listen on local-ipv4"