fdo#40835 add 4th argument to FDIST when exporting to OOXML

In ODF1.2, the 4th argument (cumulative) is optional (default true)
In Excel, the 4th argument is mandatory

Change-Id: I0d38b73af541d52f3750ba61c0864202504ca8b1
Reviewed-on: https://gerrit.libreoffice.org/13172
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>