Return correct font from gtk_font_chooser_widget_find_font

Commit 30a1c4ab fixed several memleaks including one in
gtk_font_chooser_widget_find_font.

However, the fix causes one extra call to gtk_tree_model_iter_next()
after finding the font we look for (ie pango_font_description_equal
returns TRUE): the 'increment' part of the for loop
(gtk_tree_model_iter_next) is run before the 'exit condition' of the for
loop is evaluated.

This commit reverts this part of commit 30a1c4ab and adds an extra
call to pango_font_description_free in order to fix the leak.

https://bugzilla.gnome.org/show_bug.cgi?id=739111

gtk/gtkfontchooserwidget.c

@@ -882,18 +882,18 @@ gtk_font_chooser_widget_find_font (GtkFontChooserWidget        *fontchooser,
                                    GtkTreeIter                 *iter)
 {
   GtkFontChooserWidgetPrivate *priv = fontchooser->priv;
-  PangoFontDescription *desc;
-  PangoFontFamily *family;
-  gboolean valid, found;
+  gboolean valid;
 
   if (pango_font_description_get_family (font_desc) == NULL)
     return FALSE;
 
-  found = FALSE;
   for (valid = gtk_tree_model_get_iter_first (priv->model, iter);
-       valid && !found;
+       valid;
        valid = gtk_tree_model_iter_next (priv->model, iter))
     {
+      PangoFontDescription *desc;
+      PangoFontFamily *family;
+
       gtk_tree_model_get (priv->model, iter,
                           FAMILY_COLUMN, &family,
                           -1);
@@ -905,13 +905,15 @@ gtk_font_chooser_widget_find_font (GtkFontChooserWidget        *fontchooser,
       desc = tree_model_get_font_description (priv->model, iter);
 
       pango_font_description_merge_static (desc, font_desc, FALSE);
-      if (pango_font_description_equal (desc, font_desc))
-        found = TRUE;
+      if (pango_font_description_equal (desc, font_desc)) {
+        pango_font_description_free (desc);
+        break;
+      }
 
       pango_font_description_free (desc);
     }
   
-  return found;
+  return valid;
 }
 
 static void