bug#9763: newsticker--group-manage-orphan-feeds ert test fails

[Chong Yidong]

Glenn Morris <rgm@gnu.org> writes:

> `make check' in the current trunk fails with:
>
> Running 5 tests (2011-10-15 14:01:31-0700)
>    passed  1/5  newsticker--cache-contains
>    passed  2/5  newsticker--decode-iso8601-date
>    passed  3/5  newsticker--decode-rfc822-date
> Test newsticker--group-manage-orphan-feeds backtrace:
>   newsticker--treeview-tree-update()
>   newsticker--group-manage-orphan-feeds()

The error appears to be as old as newsticker-testsuite.el itself.
Ulf, could you please fix this?  Thanks.