Add quotas to Cisco N1kv plugins supported extension aliases

When using stable/icehouse branch, due to missing quotas extension,
VM bring up errors out. With the quota table now being created as
part of folsom_initial, adding quotas to supported extension aliases
in the N1kv plugin will fix the VM bring up issue.

Change-Id: I614b6c61c4c816289a71cc1ed125e6fae269781e
Closes-bug: #1375519
Fix error adding security groups to instances with nexus

Adding security group to running instance should not
invoke the nexus plugin. Current implementation does not
validate for the 'new_host_id' and assumes it as host migration
and fails. As the nexus monolithic plugin has been removed
after icehouse, this would be merged to stable/icehouse.

Closes-Bug: #1365226

Change-Id: I9ab6b8438e6ee0698a8e2ae7ff7736f7c71b2370
Enforce required config params for ODL driver

Raise a config error during initialization if
there is no URL, username, or password specified
in the config for the OpenDayLight ML2 driver.

Also ensure core plugin deallocation after every
test [1] following the previous backport [2].

[1] https://review.openstack.org/#/c/92793/
[2] https://review.openstack.org/#/c/102329/

Closes-Bug: #1301432
Change-Id: I65fc94d3eaaade3d1402d1c82d2c1edfa7133d5a
(cherry picked from commit 2da351af7d2a10a3055020d572d357c56ba2689b)
Provide way to reserve dhcp port during failovers

This change provides a way to save the dhcp port when failing
over a network from one dhcp agent to another.  When a
dhcp-agent-network-remove is issued, the dhcp port device_id is
marked as reserved which causes it to not be deleted. When a
subsequent dhcp-agent-network-add is issued, the reserved port
is used and the device_id is corrected.  This is desirable
in order to maintain the dhcp port ip address so that dns doesn't
get impacted. Unit test added.

Closes-Bug: #1288923
(cherry picked from d5c0a37999f9e3a611a322baacabebc06b13283b)
Conflicts:
	neutron/common/utils.py
	neutron/tests/unit/test_db_plugin.py

Change-Id: I531d7ffab074b01adfe186d2c3df43ca978359cd
Merge "Provide way to reserve dhcp port during failovers" into stable/icehouse
Merge "Enforce required config params for ODL driver" into stable/icehouse
Merge "Fix error adding security groups to instances with nexus" into stable/icehouse
Merge "Add quotas to Cisco N1kv plugins supported extension aliases" into stable/icehouse
Delete DHCP port without DHCP server on a net node

A DHCP-network was deleted from one host using neutron
dhcp-agent-network-remove and then added to another host
using neutron dhcp-agent-network-add command. While the
dhcp-agent-network-remove command was in progress, the
host crashed.  As a result, the removal of the DHCP-network
was partially done. The network was disassociated from
the agent in mysql. However, the agent never made the
release_dhcp_port RPC call to delete the port -- even
after the agent restarted. The end result is that there
are two DHCP ports for the same network. One of these
is found on the host that is no longer hosting the
dhcp-server.

This fix make the DHCP agent invoke the release_dhcp_port
RPC call on a stale network whose dnsmasq process is not
running (not active). Before this change, the RPC call is
made on a stale network only when the dnsmasq process is
running.

Closes-Bug: #1244860
Change-Id: Ie0bafdac698810b5455550c306c6a75ddf91d9bb
(cherry picked from commit 8cf394b896e3644ff51edf6a0d462501fb6e6843)