GNOME Display Manager 3.8.4 Fixes Slave Sessions

GNOME Display Manager (GDM) 3.8.4 fixes slave session issues, removes unused configuration keys from schema, uses smartcard plugin when available, fixes crashing when logging out and logging in really fast, and updates PAM config for LFS. On the other hand, GNOME Display Manager (GDM) 3.9.5 makes SELinux explicitly optional on build time, tells users when their password expired, fixes various auth session issues, enables smartcard authentication by default, adds a setting for disabling password authentication, gives more friendly messages on password failure, and updates translations.