Fix bug 4576. Bug was mixed up with Empty Layout stuff. It was not always easy for...

Fix bug 4576. Bug was mixed up with Empty Layout stuff. It was not always easy for me to know then which test I needed to do, but if there are more of these, they'll be similar. Anyway, the right test here would have been:
	if (!par->forceEmptyLayout())
but in fact things can be simplified more.

Cosmetics will follow. This patch makes the action more obvious.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@24453 a592a061-630c-0410-9148-cb99ea01b6c8