Revert "rhbz#1075124: writerfilter: fix tables with negative left margin"

It appears that this was just a workaround that incidentally worked.
Making the negative value even larger (in abs value) doesn't seem to make
a difference for MSO, but LO fails again. A proper fix (better workaround?)
will follow.

This reverts commit 2e558f32ef79948858723b9781fbd388850b462b.

Change-Id: I56fd5e9d7ce9aa178f7e508f8e7ac3bc0ff2b971
Reviewed-on: https://gerrit.libreoffice.org/8763
Reviewed-by: Tor Lillqvist <tml@collabora.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>