[ut3] Detected negative delta time

[Ryan C. Gordon]

> I WAS using a 2.6.18 kernel.
> I am now using 2.6.23.12 and the latest versions of all the usual libraries.
> Both were compiled with as few options as possible.

Negative Delta Time errors in the Linux version means that 
gettimeofday() reported a time in the future, followed by a time in the 
past.

So an ntp daemon on the box can legitimately cause problems if, say, the 
system clock rolls back a few seconds as the daemon corrects it, but 
people have reported that the Con Kolivas kernel patches do some flakey 
things, too...it's possible that other kernel revisions do similar 
things. I can't say with authority what the issues are, but if 
gettimeofday() is running backwards for no good reason, that's a serious 
problem.

The next patch will change Unreal's behaviour to just consider the 
current frame as zero milliseconds, add a line to the logfile, and 
continue on...so you might get a small time distortion of a few 
milliseconds if this is a one-time occurrence, but the server won't crash.

--ryan.