[ext/rest] Catch SystemExit raised by docutils
docutils publisher may raise SystemExit which is not caught by
Exception.
Closes #3648763.
#! /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