Case C-179/18: Judgment of the Court (Tenth Chamber) of 13 February 2019 (request for a preliminary ruling from the Arbeidsrechtbank Gent — Belgium) — Ronny Rohart v Federale Pensioendienst (Reference for a preliminary ruling — Social security — Pension rights under the national pension scheme for employed persons — Refusal to take into account the period of compulsory military service completed by an official of the European Union after taking up his post — Principle of sincere cooperation)