[book] Some tweaks to fix cubicweb-documentation package generation
- Fix up PYTHONPATH setting to make sure sphinx can find cubicweb modules
- Add a few missing build-dependencies
#! /bin/sh -e#if [ "$1" = remove -o "$1" = upgrade ]; then if which install-docs >/dev/null 2>&1; then install-docs -r cubicweb-doc fifi#DEBHELPER#exit 0