[massive store] Ensure temporary metadata table get dropped even if there is some integrity errors while inserting entity values or setting back index/constraints, or any other errors. In case of exception, rollback to ensure we're not committing undesired intermediate state.

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js