[cw-ctl] use default `mkdtemp()` behaviour to store backup file internally
When using `mkdtemp(dir=instbkdir)`, a dedicated system user which hasn't the
permissions to write in /var/lib/cubicweb/instances/$INSTANCE/backup will not
be able to run the db-dump command.
#! /bin/sh -e
if [ -x "/etc/init.d/cubicweb-ctl" ]; then
invoke-rc.d cubicweb-ctl restart || true
fi
#DEBHELPER#
exit 0