Every paragraph was getting the fake tab added.

The fake tab is only inserted by LO in order to emulate the
spacing between the footnote character and the
footnote paragraph, so it is not desirable to insert it
before additional paragraphs.
The fake tab is also only removed once per
footnote during the import process, so this fake tab
was altering the document during the first round-trip.

Change-Id: Ia54cea1b04c747a021032f46f22b673fe6658995
Reviewed-on: https://gerrit.libreoffice.org/51755Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>