This patchset captures the grants of all the MariaDB users
in the backup tarball and restores the grants during the
all databases restore.
Percona tool pt-show-grants is installed to the image to
accomplish the task in this PS:
https://review.opendev.org/#/c/739149/
Change-Id: I26882956f96c961b6202b1004b8cf0faee6e73eb