pkcs11_pass_login(): check if the PIN returned by getpass is NULL
pkcs11_pass_login(): check if the PIN returned by getpass is NULL

Thanks to Andre Zepezauer for the patch
http://www.opensc-project.org/pipermail/opensc-devel/2010-September/014976.html


OpenSC/pam_pkcs11,milgner/pam_pkcs11,milgner/pam_pkcs11,OpenSC/pam_pkcs11,milgner/pam_pkcs11