stock_usability: clean-up zero-qty quants when opening quants from stock.location

When accessing stock.move.line from the show reservation on quants, in
the form view of stock.move.line, have a link to the picking

stock_usability/models/__init__.py

@@ -1,6 +1,7 @@
 from . import stock_move
 from . import stock_picking
 from . import stock_picking_type
+from . import stock_location
 from . import stock_location_route
 from . import stock_warehouse_orderpoint
 from . import stock_quant