Bug#277427: Raising priority

[Paavo Pokkinen <paveq@lyseo.edu.ouka.fi>]

Raising priority since this affects possibly everyone, not just users of
 ldap authentication. Feel free to change it back if this doesn't
justify "important".

Steps to reproduce:

1. useradd testuser
2. passwd testuser
3. expire the user's password, example /etc/shadow line:
testuser:sldbhjvmxd1vA:14244:0:101:7:::
4. Change /etc/pam.d/common-password to have just this line:
password   required     pam_deny.so
5. Restart kdm and try to login with the user, kdm tries to change the
password and fails in endless loop