update for lightdm-gtk-greeter

- add lightdm-gtk-greeter-handle-invalid-user.patch in order to fix
a NULL pointer dereference after authentication of an invalid
username has failed (bnc#857303, CVE-2014-0979)
- add lightdm-gtk-greeter-invalid-last_session.patch
fix segfault when last_session is an invalid session (lp#1161883)
- add lightdm-gtk-greeter-fix-login.patch in order to fix
login/unlock detection

Fixed bugs
bnc#857303
lightdm/X crashes on empty username
Selected Binaries
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