[quake2] Big Gun Crash

[Laurent.DESNOGUES at esterel-technologies.com]

> Seems like there's still a bug in the Big Gun transition. This was a
> known issue with ID's linux binaries ... After the Big Gun map Quake2
> crashes. Any ideas on how to fix this?
>
> I'm using the r0.0.8 release, btw.

   Same here with r0.0.7.  It looks like a cleaning dereference
a NULL pointer...  If only Purify existed for Linux!


               Laurent