cac: Free the certificate data on failure
cac: Free the certificate data on failure

Resolves:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=16819

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