[server] Initialize Repository without a tasks manager in ServerMigrationHelper.restore_database() We don't need a tasks manager here I think. Thus instantiate the Repository from its class directly instead of using config.repository() which set a tasks manager.

etc/init.d
etc/cubicweb.d
etc/bash_completion.d
usr/bin
usr/share/doc/cubicweb-ctl
var/log/cubicweb
var/lib/cubicweb/backup
var/lib/cubicweb/instances