Merge PR OCA#1625 into 16.0

Signed-off-by pedrobaeza

stock_picking_invoice_link/models/account_move.py

@@ -20,7 +20,7 @@ class AccountMove(models.Model):
     )
 
     picking_count = fields.Integer(
-        string="Pickings count", compute="_compute_picking_ids"
+        string="Pickings count", compute="_compute_picking_count"
     )
 
     @api.depends("invoice_line_ids", "invoice_line_ids.move_line_ids")
@@ -31,6 +31,11 @@ def _compute_picking_ids(self):
             )
             invoice.picking_count = len(invoice.picking_ids)
 
+    @api.depends("picking_ids")
+    def _compute_picking_count(self):
+        for invoice in self:
+            invoice.picking_count = len(invoice.picking_ids)
+
     def action_show_picking(self):
         """This function returns an action that display existing pickings
         of given invoice.