The reqif xhtml subset doesn't allow formatting of cells, which means
that the tables created with the UI and imported tables look different,
e.g. the later ones have no borders.

Fix this inconsistency by applying the default table autoformat during
import (in reqif mode). The import result looks better this way, and the
export will ignore it anyway.

Change-Id: I310770594e7a00e62f23d9df8cb16c2b95e1e44a
Reviewed-on: https://gerrit.libreoffice.org/58741Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins