Extract functions to list expected/found database indexes from check_indexes so they may be used from other contexts. Use consistent naming along the way: always use indexes, not indices.

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