After auto logout, display a message indicating what happen

The attached patch displays a message using drupal_set_message.

See also a fix for 6.x-2.5: http://drupal.org/node/1444260

Should the module be calling user_logout() instead of doing its own custom handling here?

If not, would calling session_destroy() and then drupal_goto() to let core handle session creation be preferable to creating a new session?

#886660: Logout message doubles suggests this functionality already exists?

Related core issue: #754560: Messages are lost if set just prior to logout.

Here's an alternative approach using a query string in the redirect instead of trying to store the message. This works in more situations going forwards, such as in the case of multiple tabs being open.

Sorry, patch above is for the 7.x-4.x branch

I have applied this auto logout message patch in #5 to the 7.x-4.x branch as part of #1990308

Setting back to the 6.x-4.x branch so it can be backported there.

Back ported for 6.x-4.x and committed.