Add vmware_nsx_v3 support

Sadly this is needed. We should refactor this out from all of the
plugins so we don't need to have all of these files. Adding this one
for now though.

Change-Id: Id382443fa7bef6b45237688c7e88d9e9a80a6ba1

Author: aaronorosen

lib/neutron_plugins/vmware_nsx_v3

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# This file is needed so Q_PLUGIN=vmware_nsx_v3 will work.
+
+# FIXME(salv-orlando): This function should not be here, but unfortunately
+# devstack calls it before the external plugins are fetched
+function has_neutron_plugin_security_group {
+    # 0 means True here
+    return 0
+}