Workaround for bug CASTOR-4829: tapegateway: should request positioning by blockid for recalls instead of fseq.
This forces the tape gateways recalls to be positioned by block (which should be the case in practice currently).
This workaround can be removed once the tape gateway version 2.1.15 is deployed.
This workaround is necessary for mixed environement with 2.1.14 tape gateways and 2.1.15 tapeserverd (intended at initial release time).