[devtools] remove the remaining bw compat for old-style tests It is just: * dangerously untested right now * on the path of further bw compat removal (cnxset handling) webtest drops an apparently pointless .login call Related to #3933480.

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