PowerPoint ignores a:ext cx and cy value of p:xfrm, and uses
real table width and height. PowerPoint 2010 saves files where
cx and cy contains good values, but I found files in the wild
whose cx and cy values did not match to actual table width and
height, and there was a visible difference between rendering
of Impress and PowerPoint.

Change-Id: I3f80c0cea4cac46763d449f918bb78dca1a6562d
Reviewed-on: https://gerrit.libreoffice.org/15123Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Andras Timar <andras.timar@collabora.com>