[migration] drop identity_relation if it exists
It has been generated erroneously for a while, then fixed but not properly deleted from old
databases.
Don't use IF EXISTS for sqlserver compat.
#! /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