Hide OpenGL loading screen

hw_bsp.c:

// Is this really necessary at this point..?
V_DrawCenteredString(BASEVIDWIDTH/2, 40, V_YELLOWMAP, "OPENGL MODE IS INCOMPLETE AND MAY");
V_DrawCenteredString(BASEVIDWIDTH/2, 50, V_YELLOWMAP, "NOT DISPLAY SOME SURFACES.");
V_DrawCenteredString(BASEVIDWIDTH/2, 70, V_YELLOWMAP, "USE AT SONIC'S RISK.");

No, no it's not.

But really. OpenGL hasn't been shown to crash any computers, and we do "kind of" support it. I think the loading screen is due for removal.

This also hides the console slightly earlier in the map change routine, because in OpenGL, switching maps in-console would still display the console for a split second. With the fix, the loading display is now clean and consistent with software.