[web/data] fix treeview regression (closes #3526466) Changeset 68cde7431c2c "[js] remove 3.9 bw compat (where apparently unused)" removed the use of form.callback from loadxhtml, which treeview relied on. Update to add a callback on the loadxhtml return value instead.

#! /bin/sh -e
 
case "$1" in
    purge)
	rm -rf /etc/cubicweb.d/
	rm -rf /var/log/cubicweb/
	rm -rf /var/lib/cubicweb/
    ;;
esac
 
#DEBHELPER#
 
exit 0