[test] Drop call to CubicWebConfiguration.load_cwctl_plugins in unittest_cwctl.py
This is no longer need now that we call load_available_configurations() in the
"list" command (see 5e7282bdf140).
#!/bin/sh -e
if [ "$1" = "purge" ] ; then
rm -rf /etc/cubicweb.d/
rm -rf /var/log/cubicweb/
rm -rf /var/lib/cubicweb/
fi
#DEBHELPER#
exit 0