Case T-630/11 P: Judgment of the General Court of 6 December 2012 — Strobl v Commission (Appeal — Public service — Officials — Recruitment — Open competition — Candidates whose names are included in a list of suitable candidates prior to the entry into force of the new Staff Regulations — Notice of vacancy — Appointment — Grading under the new, less favourable rules — Article 12 of Annex XIII to the Staff Regulations — Error in law — Obligation to state reasons on the part of the Civil Service Tribunal)