Create an openstack client plugin for vmware nsx, and add the some of
the extensions suport: router-type, router-size, subnet dhcp-mtu and
dns-search-domain and port provider security groups and vnic index
Work for future patches:
- More unit tests (provider-security-groups)
- Add the rest of the extensions
Change-Id: I5b335de000b310cbcbb9a2f81483fd28f8d9afea
62e5881010