Fix net-update and bridge domain deletion in N1KV plugin

1. Update only description while net-update and not publish name on VSM.
2. Delete bridge domain from VSM if bridge domain create fails.
Fix pep8 and some unit tests in N1KV plugin
Add support for newer extensions

Add l3, agent, dhcp extensions compatible with havana code.
Add router and network scheduling.
Merge branch 'n1k-havana-dev' of https://github.com/CiscoSystems/neutron into n1k-havana-dev

Conflicts:
	neutron/plugins/cisco/n1kv/n1kv_neutron_plugin.py