Bug 1321883 - remove unused variable in gtk2drawing.c; r=karlt

widget/gtk/gtk2drawing.c

@@ -1793,7 +1793,7 @@ moz_gtk_combo_box_paint(GdkDrawable* drawable, GdkRectangle* rect,
                         gboolean ishtml, GtkTextDirection direction)
 {
     GdkRectangle arrow_rect, real_arrow_rect;
-    gint arrow_size, separator_width;
+    gint separator_width;
     gboolean wide_separators;
     GtkStateType state_type = ConvertGtkState(state);
     GtkShadowType shadow_type = state->active ? GTK_SHADOW_IN : GTK_SHADOW_OUT;