turn make_relations_query into a true generator (this allows interleaving of actual entities linking and query generation) restore check botched in previous inadvertent commit

#! /bin/sh -e
#

if [ "$1" = remove -o "$1" = upgrade ]; then
  if which install-docs >/dev/null 2>&1; then
    install-docs -r cubicweb-doc
  fi
fi

#DEBHELPER#

exit 0