[sql generation] fix exists table scope pb: when iterating other solutions inner to an EXISTS subquery, we should reset variables which have this exists node as scope
#! /bin/sh -e#if [ "$1" = configure ]; then if which install-docs >/dev/null 2>&1; then install-docs -i /usr/share/doc-base/cubicweb-doc fifi#DEBHELPER#exit 0