set default to proposeStart/End to avoid Error:Typ eError: proposeStart.getInTimezone is not a function (try2)

Author: jaroslawp

interfaces/exchangeCalendar/mivExchangeCalendar.js

@@ -5566,12 +5566,14 @@ if (this.debug) this.logInfo(" ;;;; rrule:"+rrule.icalProperty.icalString);
 		}
 		if (this.debug) this.logInfo("  -------------- messageDisposition="+messageDisposition); 
 
-		var proposeStart = this.tryToSetDateValue(input.proposeStart,cal.now());
-		var proposeEnd   = this.tryToSetDateValue(input.proposeEnd,cal.now()); 
+		var proposeStart = this.tryToSetDateValue(input.proposeStart,"");
+		var proposeEnd   = this.tryToSetDateValue(input.proposeEnd,""); 
 	 	var proposeNewTime = false;
 
-		input.proposeStart = cal.toRFC3339(proposeStart.getInTimezone(this.globalFunctions.ecUTC()));
-		input.proposeEnd   = cal.toRFC3339(proposeEnd.getInTimezone(  this.globalFunctions.ecUTC())); 
+		if (proposeStart) 
+                        input.proposeStart = cal.toRFC3339(proposeStart.getInTimezone(this.globalFunctions.ecUTC()));
+		if (proposeEnd)
+                        input.proposeEnd   = cal.toRFC3339(proposeEnd.getInTimezone(  this.globalFunctions.ecUTC())); 
 
 		if( input.proposeStart && input.proposeEnd ){
 			proposeNewTime = true;