remote_apt_keys variable in base image should be base_remote_apt_keys for consistency

[Maksim Malchuk]

The customization format of the variable name should contain the
<image_name> [1]. The name of the 'remote_apt_keys' variable [2]
incorrect, so customization is ignored.

1. https://docs.openstack.org/kolla/latest/admin/image-building.html#dockerfile-customisation
2. https://opendev.org/openstack/kolla/src/commit/c8da82967946d5252c557c20423684bed383c228/docker/base/Dockerfile.j2#L335

[Mark Goddard (mgoddard)]

While the variable name is inconsistent and confusing, this is not the part that the code checks.

[Maksim Malchuk (mmalchuk)]

The variable name should be in the correct format to be overriden. The code of the filter is here: https://opendev.org/openstack/kolla/src/commit/c8da82967946d5252c557c20423684bed383c228/kolla/template/filters.py#L20-L36

[Mark Goddard (mgoddard)]

As discussed - the override will work regardless of the variable name.