Initialize linked list for recurrent items

When switching to the generic linked list implementation for recurring
events in 9fab248 (Use generic lists for recurring apointments and
events., 2011-04-16), no initialization routine for the list of
recurring events was added. Fix this and properly initialize the list on
startup.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/calcurse.c

@@ -518,6 +518,7 @@ int main(int argc, char **argv)
 
 	/* Initialize non-thread-safe data structures. */
 	event_llist_init();
+	recur_event_llist_init();
 	todo_init_list();
 
 	/*