[cwconfig] Fix exception handling when building the cube dependency graph UnorderableGraph exceptions do not have a 'cycles' property. A simple cast to str does the job.

#! /bin/sh -e

if [ -x "/etc/init.d/cubicweb-ctl" ]; then
    invoke-rc.d cubicweb-ctl restart || true
fi
 
 
#DEBHELPER#
 
exit 0