Replace bullet char before write out font description
since it may be altered if bullet font has been changed
(i.e. StarSymbol to WingDings ).

Change-Id: I0461cc0a5e4628b36177602bba7ed7f74a0751eb
Reviewed-on: https://gerrit.libreoffice.org/17376Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>
Reviewed-on: https://gerrit.libreoffice.org/18318Reviewed-by: Mark Hung <marklh9@gmail.com>