apic_aim_vm_name_updates column host_id is too short for openstack-ansible installations

[Joakim Hindersson]

The commit 357fbd4d833415b7e857644767a24a5ddd67a387 introduced a new table in the neutron database named apic_aim_vm_name_updates. It contains a column with name host_id which is supposed to be filled with the hostname of the machine running the neutron server to avoid multiple instances doing the same work uneccessarily and maybe to avoid some race conditions.

When using GBP in an environment deployed by openstack-ansible the hostname of the machines can get really long, in our case 57 characters and causes the insert to the table above to fail because it is limited to 36 characters.

Could we please patch this column to alllow for up to 64 characters or even 128 and backport this fix to pike?

Attaching error message for reference (the hostname is redacted but the length of it is intact)
2019-03-05 09:25:03.863 10756 ERROR oslo.service.loopingcall [-] Fixed interval looping call 'gbpservice.neutron.plugins.ml2plus.drivers.apic_aim.mechanism_driver.ApicMechanismDriver._update_nova_vm_name_cache' failed: DBDataError: (pymysql.err.DataError) (1406, u"Data too long for column 'host_id' at row 1")
[SQL: u'INSERT INTO apic_aim_vm_name_updates (host_id, last_incremental_update_time, last_full_update_time) VALUES (%(host_id)s, %(last_incremental_update_time)s, %(last_full_update_time)s)'] [parameters: {'host_id': 'id-xxx-xxxx-xxxx-xxxx-neutron-server-container-ce90de6d', 'last_incremental_update_time': da
tetime.datetime(2019, 3, 5, 9, 25, 1, 908846), 'last_full_update_time': datetime.datetime(2019, 3, 5, 9, 25, 1, 908846)}]