Get rid of some annoying sys_vgui cruft in startup.

Here's another one from the let's-get-rid-of-completely-obsolete-stuff department. This ancient sys_vgui call isn't serving any purpose any more (and surely won't in the future), it only spits out an annoying legacy command warning in the console during startup.

Just a quick reminder that this is ready to go in as well. I re-triggered the two runners which were unavailable for some reason. This shouldn't warrant a big discussion, it just removes that useless legacy tcl command warning, nothing else. So it would be nice if you could just merge and be done with it, thanks.

merged