Shapes were deformed because flipping wasn't considered when removing
the rotation. Also WriteShapeTransformation needs information about
flipping to convert the angle correctly.

Change-Id: I7d485e93c00e02b9ec6c73ad6ae2876e5bc6360a
Reviewed-on: https://gerrit.libreoffice.org/41462Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tamás Zolnai <tamas.zolnai@collabora.com>