pkcs15-init: Fixed segfault
pkcs15-init: Fixed segfault

regression introduced in de7aaa4197cd5a3d97ed145716f75d9594158d2c

fixes https://github.com/OpenSC/OpenSC/issues/934
closes https://github.com/OpenSC/OpenSC/pull/935

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