- Profit & Loss was showing negative value for profit or loss on previous period
- Profit & Loss was not showing previous period loss if current period is a profit
- Balance Sheet was not calculating properly net profit for previous period

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@32077 20353a03-c40f-0410-a6d1-a30d3c3de9de