Use more generic parameter name to cut association with gconf

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23214 57a11ea4-9604-0410-9ed3-97b8803252fd
Prepare for GSettings conversion

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23215 57a11ea4-9604-0410-9ed3-97b8803252fd