[FIX] stock: Transfering the pack

When transfering the pack, the priority to the moves in state "assigned"
or partially_available(=true) must be given.

Used case (steps):

-set warehouse with three steps to delivery
-create one product A with qty on hand 10
-create sale order with first line product A by qty 2 and the second line with product A with qty 10
-confirm sale order
-check availability
-transfer pick by qty 10
-transfer pack by qty 10

The pack couldn't be transered

Now the pack is transfered.

Closes: #10764

opw:668682

addons/stock/stock.py

@@ -1268,7 +1268,8 @@ class stock_picking(osv.osv):
         prod2move_ids = {}
         still_to_do = []
         #make a dictionary giving for each product, the moves and related quantity that can be used in operation links
-        for move in [x for x in picking.move_lines if x.state not in ('done', 'cancel')]:
+        moves = sorted([x for x in picking.move_lines if x.state not in ('done', 'cancel')], key=lambda x: (((x.state == 'assigned') and -2 or 0) + (x.partially_available and -1 or 0)))
+        for move in moves:
             if not prod2move_ids.get(move.product_id.id):
                 prod2move_ids[move.product_id.id] = [{'move': move, 'remaining_qty': move.product_qty}]
             else: