Run nova-novncproxy binary in the nova GIT trree

The nova-novncproxy binary was pulled into the nova GIT tree
several months back, so devstack should run that version,
rather than the legacy version from the noVNC GIT tree.

Change-Id: I289989d5c0831c75117f059dd8f2decb1f9d3a90
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Merge "Run nova-novncproxy binary in the nova GIT trree"