If the document did not specify a preferred table width, then
the indent was completely wrong. I don't think the "else" clause
ever provided a correct value.
See https://bz.apache.org/ooo/attachment.cgi?id=63705&action=diff

These documents don't round-trip at all, so making changes
here ought to be fairly regression-safe since the documents are
read-only anyway.

Change-Id: I6308ffd22b6f7ce60b9780e00b68bc6f8b09a6fa
Reviewed-on: https://gerrit.libreoffice.org/41664Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>