Remove calls to cogl_disable_fog

I can't think of any reason why it would do this and there's no
comment explaining it so let's just remove it. The global fog state
has been removed in Cogl 2.0 so it will cause problems later.

Reviewed-by: Emmanuele Bassi <ebassi@linux.intel.com>

clutter/clutter-stage.c

@@ -696,8 +696,6 @@ clutter_stage_paint (ClutterActor *self)
   if (!STAGE_NO_CLEAR_ON_PAINT (self))
     clear_flags |= COGL_BUFFER_BIT_COLOR;
 
-  cogl_disable_fog ();
-
   CLUTTER_TIMER_START (_clutter_uprof_context, stage_clear_timer);
   /* we use the real alpha to clear the stage if :use-alpha is
    * set; the effect depends entirely on the Clutter backend
@@ -1500,7 +1498,6 @@ _clutter_stage_do_pick (ClutterStage   *stage,
   CLUTTER_NOTE (PICK, "Performing %s pick at %i,%i",
                 is_clipped ? "clippped" : "full", x, y);
 
-  cogl_disable_fog ();
   cogl_color_init_from_4ub (&stage_pick_id, 255, 255, 255, 255);
   CLUTTER_TIMER_START (_clutter_uprof_context, pick_clear);
   cogl_clear (&stage_pick_id,

clutter/clutter-texture.c

@@ -556,7 +556,6 @@ update_fbo (ClutterActor *self)
   cogl_clear (&transparent_col,
               COGL_BUFFER_BIT_COLOR |
               COGL_BUFFER_BIT_DEPTH);
-  cogl_disable_fog ();
 
   /* Render the actor to the fbo */
   clutter_actor_paint (priv->fbo_source);