[dataimport] Add a ``flush`` method for all stores. For ``ObjectStore``, ``RQLObjectStore`` and ``NoHookRQLObjectStore`` the method tries to call the ``commit`` method. For ``SQLGenObjectStore``, the ``flush`` method is basically unchanged with respect to previous changesets.

#! /bin/sh -e
 
case "$1" in
    remove)
	if [ -x "/etc/init.d/cubicweb-ctl" ]; then
	    invoke-rc.d cubicweb-ctl stop || true
	fi
    ;;
esac
 
#DEBHELPER#
 
exit 0