[repo creation] removing existing entities of 'single' cardinality relatino should be considered as 'activeintegrity' hook. Also don't disable that category during repo creation to avoid pb such as two default workflows for one entity types

usr/lib/python2.4/site-packages/cubicweb/
etc/init.d
etc/cubicweb.d
etc/bash_completion.d
usr/bin
usr/share/doc/cubicweb-ctl
var/run/cubicweb
var/log/cubicweb
var/lib/cubicweb/backup
var/lib/cubicweb/instances