When deleting unsuitable addresses in get_interface_address6_list(), to
avoid reordering IPv6 interface addresses and keep the order returned by
the OS, use SMARTLIST_DEL_CURRENT_KEEPORDER() instead of
SMARTLIST_DEL_CURRENT().
This issue was reported by René Mayrhofer.
[Closes ticket 20163; changes file written by teor. This paragraph
added by nickm]
