Bug 20656: Don't print lines that have no balance on print summary

Bug 20656: Don't print lines that have no balance on print summary

To test:
1 - Add at least two fines to a patron
2 - Pay off one of them
3 - Print summary - all 3 lines show
4 - Apply patch
5 - Print summary - only line with balance shows

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 0fd329724b58c34d850a5b5f162ad0c0f2428eb4)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>