Problem:
- Table cell border width is not exported.
i.e lnL, lnR, lnT, LnB are not exported inside the tcPr.

XML Difference:
Original :
<a:lnT w = "76200">

After RT : tag is missing.

Solution : Added solution for Table cell border width.

Change-Id: I19185f2ad176325bf7990c9da6becc66557c717b
Reviewed-on: https://gerrit.libreoffice.org/15350Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>