Always trigger a write if no pages are written

If a previous write was canceled we can end up in the situation where
the layout reports "not changes since layout" but no pages have been
written.

In this case we have to trigger a write even if the layout reports that
nothing changed.

Fixes: 24110832
Change-Id: I4b3f69581e63f4084cd3712861288ded7d9c9249