[repository] when deleting relations of a deleted external entity, we should skip non-crossable relation (closes #1973680) elses this may lead to things as described in the ticket...

#! /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