In the Dockerfile of cinder-volume, the "kolla_extend_start" script
will be overwritten, and it will cause the cinder-volume container
doesn't create /var/log/kolla/cinder folder.
The name of the start script should be "kolla_cinder_extend_start" in
cinder-volume container.
Change-Id: I7251792a4fbe1442e2ffc5ebd9e41bd9cdc33568
Closes-Bug: #1638839
6c2d02a614