am 8dcd2932: set the attendee email when changing your own attendance in the attendees table, so some calendar provider code can update the self attendance in the Event.

Merge commit '8dcd29326bd6e6be91e22b88c422a4d7fc24dd3b' into eclair-mr2

* commit '8dcd29326bd6e6be91e22b88c422a4d7fc24dd3b':
  set the attendee email when changing your own attendance in the attendees table, so some calendar provider code can update the self attendance in the Event.