[FIX] hr_payroll: put a check for the structure used in the contract. When any structure

is already assigned into contract and that is deleted, it will affet the Payslips which were already created and will have [False] value.

bzr revid: rha@tinyerp.com-20131223101841-6fbwfm90gn7sj17m

addons/hr_payroll/hr_payroll.py

@@ -146,7 +146,9 @@ class hr_contract(osv.osv):
         @return: the structures linked to the given contracts, ordered by hierachy (parent=False first, then first level children and so on) and without duplicata
         """
         all_structures = []
-        structure_ids = [contract.struct_id.id for contract in self.browse(cr, uid, contract_ids, context=context)]
+        structure_ids = [contract.struct_id.id for contract in self.browse(cr, uid, contract_ids, context=context) if contract.struct_id]
+        if not structure_ids:
+            return []
         return list(set(self.pool.get('hr.payroll.structure')._get_parent_structure(cr, uid, structure_ids, context=context)))
 
 hr_contract()