Fix issue with invisible recurring appointments

Fixes that recurring appointments goes invisible
when hit by the failsafe limit.

There is still a hard limit in RecurrenceProcessor,
but at least this limit is applied on a per-event
basis, meaning that it's always possible to create
new recurring appointments without them going invisible.

Change-Id: I6c9e1e10db78e1b73ea9f2b7104621fbbd906452