Avoid double fclose() in some error cases.
Avoid double fclose() in some error cases.

Problem reported (and patched) by Lingzhu Xiang <xianglingzhu@gmail.com>
in http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=657524

madrat-/yubico-pam,eworm-de/yubico-pam,madrat-/yubico-pam,Yubico/yubico-pam,Yubico/yubico-pam,eworm-de/yubico-pam,Yubico/yubico-pam,madrat-/yubico-pam,eworm-de/yubico-pam