[debian] Remove unused/redundant entries from debian/cubicweb-ctl.dirs * bash completion entry produces a lintian warning "package-installs-into-obsolete-dir etc/bash_completion.d/", and it does not install bash completion. * doc directory should be handled automatically.

etc/init.d
etc/cubicweb.d
usr/bin
var/log/cubicweb
var/lib/cubicweb/backup
var/lib/cubicweb/instances