[server] Add missing indices for undo support (closes #3259691) The tables used by the 'undo' feature were missing some indices, which among other things triggered repeated sequential scans when deleting old transactions.

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