Security groups: prevent race for default security group creation

When a VM is booted via the Nova the client connection is created
with an admin user. This causes problems when creating the neutron
port. That is, there may be a race for the creation of the default
security group for the tenant.
The problem was introduced by commit acf44dba26ca8dca47bfb5fb2916807f9f4e2060

Change-Id: Ie0199c71231a322704f1f49995facde09c92da25
Closes-bug: #1372570
Deletes floating ip related connection states

When a floating ip is dissociated with a port, the current
connection with the floating ip is still working. This patch
will clear the connection state and cut off the connection
immediately.

Since conntrack -D will return 1, which is not an error code,
so add extra_ok_codes argument to execute methods.

Change-Id: Ia9bd7ae243a0859dcb97e2fa939f7d16f9c2456c
Closes-Bug: 1334926
Merge "Deletes floating ip related connection states"
Merge "Security groups: prevent race for default security group creation"
Merge branch 'master' of https://github.com/openstack/quantum