Distributed background correct needs to happen on all processes.

Previously background correct only happened on display processes after
the image was collected.  Now we encourage distributed correction before
collection.  In this case, it was wrong to not correct on non-display
processes.

src/ice-t/draw.c

@@ -190,8 +190,7 @@ static void drawUseBackgroundColor(const IceTFloat *background_color)
         icetStateSetInteger(ICET_BACKGROUND_COLOR_WORD, 0);
 
         icetGetIntegerv(ICET_TILE_DISPLAYED, &display_tile);
-        if (   (display_tile >= 0)
-            && (background_color_word != 0)
+        if (   (background_color_word != 0)
             && icetIsEnabled(ICET_CORRECT_COLORED_BACKGROUND) ) {
             icetStateSetBoolean(ICET_NEED_BACKGROUND_CORRECTION, ICET_TRUE);
         } else {