#98 gtk-client crash on invalid launch

[Jason Dorje Short]

Due to an unrelated bug, I ended up with ggzcore and/or
ggz-gtk being confused about its state and activating
the "launch" button in the entry room.

When I, just out of curiosity, clicked this button, the
client crashed.

The backtrace is rather short:

(gdb) bt
#0 0x4032296d in memset () from /lib/libc.so.6
#1 0x0805e9f1 in create_dlg_launch () at launch.c:535