Replace CV_NETVAR with CV_NOTINNET for cv_renderhitbox

The CV_NETVAR flag being used for cvars not registered in a dedicated server context will completely mess with the internal netid to cvar linkage.
And I'm not really keen on registering a cvar purely for rendering on dedicated servers, so let's just prevent renderhitbox from being changed in netgames entirely.

src/r_bbox.c

@@ -34,7 +34,7 @@ static CV_PossibleValue_t renderhitbox_cons_t[] = {
 	{RENDERHITBOX_RINGS, "Rings"},
 	{0}};
 
-consvar_t cv_renderhitbox = CVAR_INIT ("renderhitbox", "Off", CV_CHEAT|CV_NETVAR, renderhitbox_cons_t, NULL);
+consvar_t cv_renderhitbox = CVAR_INIT ("renderhitbox", "Off", CV_CHEAT|CV_NOTINNET, renderhitbox_cons_t, NULL);
 consvar_t cv_renderhitboxinterpolation = CVAR_INIT ("renderhitbox_interpolation", "On", CV_SAVE, CV_OnOff, NULL);
 consvar_t cv_renderhitboxgldepth = CVAR_INIT ("renderhitbox_gldepth", "Off", CV_SAVE, CV_OnOff, NULL);