[6.1] account_bank - post_write method not single id safe

Hello,

While using some ooor script, I figured out that the method write crash if you try to use a single id instead of a list of ids.

Traceback (most recent call last):
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/wsgi.py", line 77, in xmlrpc_return
    result = openerp.netsvc.dispatch_rpc(service, method, params)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/netsvc.py", line 325, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/service/web_services.py", line 580, in dispatch
    res = fn(db, uid, *params)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/osv/osv.py", line 120, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/osv/osv.py", line 172, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/osv/osv.py", line 163, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/addons/account/account_bank.py", line 38, in write
    return result
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/addons/account/account_bank.py", line 44, in post_write
    if bank.company_id and not bank.journal_id:
  File "/home/yvaucher/Projects/dnag_openerp_6_1/test/src/server/openerp/osv/orm.py", line 490, in __iter__
    raise NotImplementedError("Iteration is not allowed on %s" % self)
NotImplementedError: Iteration is not allowed on browse_record(res.partner.bank, 17)

This issue come from method post_write that is expecting a list of ids.

A patch is attached.

Regards,
Yannick