Debugging file save combo

[Owen Taylor <otaylor redhat com>]

OK, I got to the point of having a GTK+-2.3.5 tarball all ready to
go locally, but on a little experimentation found that the save
mode of the FileChooser with the new folder selection code was
too buggy to release.

After some debugging, the first bug I tracked down was in GtkComboBox -

 gtk_combo_box_menu_row_inserted/deleted/etc

update the *menu* on rows inserted, deleted and reordered, but don't
properly handle updating the cell view or active index:

 - They aren't hooked up at all in list mode
 - They return immediately if the menu isn't shown yet
 - They don't handle deletions, etc, that would change the 
   active index by removing rows before it (or reordering that
   item earlier)

I put in a few quick fixes there (not committed, because they weren't
really finished) but things still aren't working right - with my
fixes, I get the file chooser dying immediately with:

  Gtk-ERROR **: file gtkfilechooserdefault.c: line 947
(shortcuts_remove_rows): should not be reached

I think this is likely a GtkFileChooser bug, not a GtkComboBox bug.

Since the combobox and new filechooser code are what we need to test
most for 2.3.5, I don't want to back out the save-location combo and do
2.3.5 without it. But I'll see where we get on this tomorrow and if we
don't have anything likely looking by the afternoon we may want
to consider that anyways and do a 2.3.6 later in the week.

Regards,
						Owen