The function responsible for freeing a recurring appointment or event
did not free the linked lists contained in the `struct rpt` holding the
recurrence rules. This led to memory leaks if a user had recurring
appointments or events.
Found with ASAN.
Signed-off-by: Max Kunzelmann <max@mxzero.net>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>