[FIX] if an action descriptor is precisely ``false``, treat it as an ir_action_close...

[FIX] if an action descriptor is precisely ``false``, treat it as an ir_action_close                                                                                   ~/projects/tiny/web/current

Can be seen in e.g. Quotations > [More sidebar] > Sale: Mark Unread:
it's a server action which just returns ``False``, the handler
resulted in a noop but also produced an error message in the browser
console ("No type for action false").

Convert ``false`` (identity-tested) into an ir_action_close in
do_action, before actually mucking into the action descriptor.

bzr revid: xmo@openerp.com-20121129101137-g01nd49hnlg2odfs