paste from system from the top left of selection

For example,
1. echo -e "5,6\n7,8"
2. select the lines and copy them to clipboard
3. select an area in Calc, starting from bottom right
4. paste
5. select comma as data separator in the CSV import dialog

I think most people would expect the data to appear in the selected
area, but currently it would be inserted starting from active cell
(which is the bottom right cell of the selection).

Change-Id: Ief0e05deda18928a832dca2a261f8493ac9a03a9
Reviewed-on: https://gerrit.libreoffice.org/13410
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>