RSVP: view change callback is not handled and membership list needs to be updated

2 problems:

#1 A view is handled in the down() callback, however, as RSVP is usually at the top of the stack, this is never called !
SOLUTION: handle the view callback in up().

#2 In down(), if we create an Entry with

, but - before we add it to the ids hashmap - a new view

is installed, Entry will never get updated.
SOLUTION: update the Entry after adding it to the ids hashmap