Intention:
Make e.g. [1+SWITCH(1;1;1;6)] work. Without this fix, the result is
7 but should be 2.

Change-Id: I2a72e458e5458c02c3ce2f4214b86ba13f7b1d11
Reviewed-on: https://gerrit.libreoffice.org/27664Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>