it's not enough to compare != end(), you also need to compare the key
against the iterator result

Change-Id: Ide5f151ba2297a35e5546f47fbc3c53cbe5ab533
Reviewed-on: https://gerrit.libreoffice.org/62014
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>