[REVIEW-3-5] fix for fdo#44742, xls cell border import and export use different width settings

[Markus Mohrhard]

Hey,

[1] prevents that cell borders are incorrectly saved to xls after
import from xls. The problem is that one of the old go-oo patches
changed the defaults for xls import but did not adjust the values for
xls export. I now moved the border width information into a common
header file so that these are shared between import and export.

This patch should be safe and fixes one more of the border problems so
I hope we can get this into 3-5.

Regards,
Markus

[1] http://cgit.freedesktop.org/libreoffice/core/commit/?id=4ab9719f15baddbc60b96d86d2e0878e79a6ddf7