Joined Cases C-444/09 and C-456/09: Judgment of the Court (Second Chamber) of 22 December 2010 (reference for a preliminary ruling from the Juzgado de lo Contencioso-Administrativo No 3 de A Coruña (Spain) and the Juzgado de lo Contencioso-Administrativo No 3 de Pontevedra (Spain)) — Rosa María Gavieiro Gavieiro (C-444/09), Ana María Iglesias Torres (C-456/09) v Consellería de Educación e Ordenación Universitaria de la Xunta de Galicia (Social Policy — Directive 1999/70/EC — Clause 4 of the framework agreement on fixed-term work concluded by ETUC, UNICE and CEEP — Principle of non-discrimination — Application of the framework agreement to the interim staff of an Autonomous Community — National rules establishing different treatment in respect of the award of a length-of-service increment on the basis of the temporary nature of the employment relationship — Obligation to recognise, with retrospective effect, the right to the length-of-service increment)