fdo#39440 sal: reduce scope of local variables

This addresses some cppcheck warnings.

Change-Id: Id5f90757571e76a2c05a4cbd37020e1f6a6b2033
Reviewed-on: https://gerrit.libreoffice.org/13544
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>