[FIX] hr_expense: Creation of entries from several expense lines

When posting journal entries for an hr.expense.sheet with several expense lines
(by clicking on the button "Post journal entries"), all the account move lines
created for the same sheet must be linked to the same account move because
the model hr.expense.sheet has just a field "account_move_id" to access all the entries
(by clicking on button "Accounting Entries")

opw:715523,709930,725798,716239

addons/hr_expense/models/hr_expense.py

@@ -172,19 +172,24 @@ class HrExpense(models.Model):
         '''
         main function that is called when trying to create the accounting entries related to an expense
         '''
+        move_group_by_sheet = {}
         for expense in self:
             journal = expense.sheet_id.bank_journal_id if expense.payment_mode == 'company_account' else expense.sheet_id.journal_id
             #create the move that will contain the accounting entries
             acc_date = expense.sheet_id.accounting_date or expense.date
-            move = self.env['account.move'].create({
-                'journal_id': journal.id,
-                'company_id': self.env.user.company_id.id,
-                'date': acc_date,
-                'ref': expense.sheet_id.name,
-                # force the name to the default value, to avoid an eventual 'default_name' in the context
-                # to set it to '' which cause no number to be given to the account.move when posted.
-                'name': '/',
-            })
+            if not expense.sheet_id.id in move_group_by_sheet:
+                move = self.env['account.move'].create({
+                    'journal_id': journal.id,
+                    'company_id': self.env.user.company_id.id,
+                    'date': acc_date,
+                    'ref': expense.sheet_id.name,
+                    # force the name to the default value, to avoid an eventual 'default_name' in the context
+                    # to set it to '' which cause no number to be given to the account.move when posted.
+                    'name': '/',
+                })
+                move_group_by_sheet[expense.sheet_id.id] = move
+            else:
+                move = move_group_by_sheet[expense.sheet_id.id]
             company_currency = expense.company_id.currency_id
             diff_currency_p = expense.currency_id != company_currency
             #one account.move.line per expense (+taxes..)
@@ -235,9 +240,10 @@ class HrExpense(models.Model):
             lines = map(lambda x: (0, 0, expense._prepare_move_line(x)), move_lines)
             move.with_context(dont_create_taxes=True).write({'line_ids': lines})
             expense.sheet_id.write({'account_move_id': move.id})
-            move.post()
             if expense.payment_mode == 'company_account':
                 expense.sheet_id.paid_expense_sheets()
+        for move in move_group_by_sheet.values():
+            move.post()
         return True
 
     @api.multi