This fixes docx import of page breaks in empty paragraphs, when the
compat option in question is set.

Even empty paragraphs have an "end of paragraph" character in dmapper:
import page breaks there, instead of delaying the import till the
all-catcher importer at the start of the next paragraph.

Change-Id: Ie5c37042b3c445e0669771d15c8eb46380192db3