Disable more mariadb options during backup restoration:
- relax durability
- disable binlogs
- disable slow log
Bits of this commit were already accidentally (but harmlessly) pushed as
part of
  commit 5bde847f
  Author: Vincent Pelletier <vincent@nexedi.com>
  Date:   Tue Feb 21 16:02:21 2017 +0900

    stack.erp5: Avoid duplicating mariadb service paths.