This change adds the ability to configure Huawei backends in Cinder
as described in [1] by adding the additional configuration XML files
to the cinder-volume containers. However, this change does not
provide the default configuration options for the cinder.conf due to
the wide range of Huawei hardware that is supported. Operators may
also wish to configure multiple backends, so they should use the
standard method of overriding backend sections to use these XML
files, as described in [2].

1. https://docs.openstack.org/cinder/latest/configuration/block-storage/drivers/huawei-storage-driver.html
2. https://docs.openstack.org/kolla-ansible/latest/admin/advanced-configuration.html#openstack-service-configuration-in-kolla



Implements: blueprint cinder-huawei-backend
Co-Authored-By: Juan Pablo Suazo <jsuazo@whitestack.com>
Co-Authored-By: Maksim Malchuk <maksim.malchuk@gmail.com>
Change-Id: Ic8624b2e956b1f48f5fb96d6d8a0150b67236d20
Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>