cac: Fail if the read instruction does not return anything
cac: Fail if the read instruction does not return anything

To avoid infinite loop on "unfriendly" cards, we assume that
read data instruction always returns some data. It it does not,
we can safely assume the file is not there or it is not the card
we are looking for.

AktivCo/OpenSC,CardContact/OpenSC,fabled/OpenSC,fabled/OpenSC,philipWendland/OpenSC,OpenSC/OpenSC,viktorTarasov/OpenSC-SM,metsma/OpenSC,hongquan/OpenSC-main,AktivCo/OpenSC,frankmorgner/OpenSC,OpenSC/OpenSC,dengert/OpenSC,philipWendland/OpenSC,hhonkanen/OpenSC,philipWendland/OpenSC,AktivCo/OpenSC,mouse07410/OpenSC,rickyepoderi/OpenSC,metsma/OpenSC,frankmorgner/OpenSC,hhonkanen/OpenSC,CardContact/OpenSC,Jakuje/OpenSC,fabled/OpenSC,viktorTarasov/OpenSC-SM,hongquan/OpenSC-main,LudovicRousseau/OpenSC,Jakuje/OpenSC,dengert/OpenSC,dengert/OpenSC,Jakuje/OpenSC,OpenSC/OpenSC,mouse07410/OpenSC,frankmorgner/OpenSC,rickyepoderi/OpenSC,hongquan/OpenSC-main,fabled/OpenSC,rickyepoderi/OpenSC,mouse07410/OpenSC,frankmorgner/OpenSC,metsma/OpenSC,Jakuje/OpenSC,viktorTarasov/OpenSC-SM,CardContact/OpenSC,LudovicRousseau/OpenSC,hhonkanen/OpenSC,LudovicRousseau/OpenSC