Use proper conversion modifier for unsigned int

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23379 57a11ea4-9604-0410-9ed3-97b8803252fd
Bug 711294 - Gnucash repeatedly ask associated income account when import qfx file

Patch by Kuang-che Wu <kcwu@csie.org>

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23380 57a11ea4-9604-0410-9ed3-97b8803252fd