[FIX] the problem of Empty list of journals when trying to create invoice from picking

lp bug: https://launchpad.net/bugs/1001806 fixed

bzr revid: rmu@tinyerp.com-20120521062736-qkd3d20k0pxzn2l8

addons/stock/wizard/stock_invoice_onshipping.py

@@ -36,7 +36,7 @@ class stock_invoice_onshipping(osv.osv_memory):
             context = {}
 
         model = context.get('active_model')
-        if not model or model != 'stock.picking':
+        if not model or 'stock.picking' not in model:
             return []
 
         model_pool = self.pool.get(model)