Bug#1798: /etc/login has no effect when using xdm from other machines

[Winfried Truemper <winni@ElFi.MI.Uni-Koeln.DE>]

Package: xdm

Instead of testing for "/etc/nologin" in "/etc/X11/Xstartup", the testing
should be done in "/etc/X11/Xsession".
And a "-geometry +100+100" will make it look nicer; probably a "-bg
yellow" will wake up the user ...

Winfried