[datafeed] do NOT call commit in DataFeedXMLParser.process() (closes #10928592) and so, remove more useless code. Doing a commit in DataFeedXMLParser.process() is a bad idea because this method is called for every imported/updated entity, before handling deletions. So if we commit here, odds are quite high that we're violating some integrity constraint and end up with a ValidationError.

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