[FIX] trackers: Only check for fields when there are some to list (prevents 0 items found if no fields set to "list")
[FIX] trackers: Only check for fields when there are some to list (prevents 0 items found if no fields set to "list")

git-svn-id: a7fabbc6a7c54ea5c67cbd16bd322330fd10cc35@35739 b456876b-0849-0410-b77d-98878d47e9d5

tikiorg/tiki,oregional/tiki,changi67/tiki,oregional/tiki,changi67/tiki,changi67/tiki,oregional/tiki,tikiorg/tiki,changi67/tiki,changi67/tiki,tikiorg/tiki,tikiorg/tiki,oregional/tiki