Updated openstack/openstack
Project: openstack/neutron  a4531b7945cc979b522467091fe87f95c1a8ee9e

Drop and recreate FK if adding new PK to routerl3bindings

Since MySQL 5.6 FK columns cannot be altered. As a workaround we can
drop the FK before ALTER COLUMN and then recreate it.

Change-Id: Icd1b3075cf29a6b0c477a4ddea2e6ebee91baef8
Closes-Bug: 1384555