This rev. increases the wait interval of the redirect handler
called when a document is clicked in a mail thread (e.g. in the
'Inbox' in Discuss). This increases the protection against
double-clicks (preventing the document from being opened twice,
thus making twice the required RPCs, and from appearing twice in
the breadcrumbs).
A more robust solution (at the ActionManager level) will be
developed for saas-11.2 (where the ActionManager has been
refactored and is testable).