Fix MSI comment when productname contains whitespace

Change-Id: I5c6383cd383eef02cc9e8a6f4798b928763e46c6
Reviewed-on: https://gerrit.libreoffice.org/11994
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>