Since this bind-mount isn't shared with any other container, remove its
"relabel" flag (:z).
This relabelling is especially useless since the directory creation AND
openstack-selinux sets its type to a sensible value. We can therefore
remove it and prevent possible issues in the future.
Closes-Bug: #1888216
Change-Id: I1e7ddb3bbb3825db805f137ea9a2501878f380d4
(cherry picked from commit 98d2271d1a)
0d587d8ce0