Do not enforce the Vrect to have even width and heights.

I really don't see why this constraint was ever necessary. It leads to
one line of pixels not rendered either at the bottom or the right edge
of the screen. In GL1 for whatever reasons this line is just black, in
GL3 garbage is drawn.

src/client/cl_screen.c

@@ -351,10 +351,7 @@ SCR_CalcVrect(void)
 	size = scr_viewsize->value;
 
 	scr_vrect.width = viddef.width * size / 100;
-	scr_vrect.width &= ~1;
-
 	scr_vrect.height = viddef.height * size / 100;
-	scr_vrect.height &= ~1;
 
 	scr_vrect.x = (viddef.width - scr_vrect.width) / 2;
 	scr_vrect.y = (viddef.height - scr_vrect.height) / 2;