Calendar: single-appointment to recurring fix

(cherry picked from commit 004d1069)

entity/Appointment_entity/recordcontainers/jdito/onUpdate.js

@@ -56,7 +56,7 @@ if(event)
             event[calendars.REMINDER_DURATION] = fields["REMINDER.value"];
         }
         
-        if(event[calendars.RRULE])
+        if(fields["RRULE.value"])
             event[calendars.RRULE] = [fields["RRULE.value"]];
         
         // Adds the required X-Header for status actions needed by Exchange and Domino