reduce scope of local variables

This addresses some cppcheck warnings.

Change-Id: I864a4e84326633d33f09324247cbe439fba801c8
Reviewed-on: https://gerrit.libreoffice.org/13336
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>