Please update Sddm package with package in experimental

[MERLIN Philippe]

Hello,
I know Debian package is frozen, but actually the Sddm package is bugged.
It ignores the instructions given in the /etc/sddm.conf file as HideShells or 
HideUsers. These bugs are serious, the next version of Debian should not 
contain these errors.
In experimental its OK.
Philippe Merlin