fix addUserTag event v2

@@ -45,11 +45,15 @@ import SwiftEventBus
                 } else if (eventArray[1] == "addUserTag") {
                     let questionnaireEvent = swiftApi.QuestionnaireEventModel()
                     questionnaireEvent._name = String(eventArray[1])
-                    questionnaireEvent._parameter = String(eventArray[2])
+                    if (eventArray.count > 2) {
+                        questionnaireEvent._parameter = String(eventArray[2])
+                        swiftApi().setUserTag(String(eventArray[2]))
+                    } else {
+                        questionnaireEvent._parameter = ""
+                        swiftApi().setUserTag("")
+                    }
                     SwiftEventBus.post("questionnaire", sender: questionnaireEvent)
                     
-                    swiftApi().setUserTag(String(eventArray[2]))
-                    
                 } else if (eventArray[1] == "couponRetrieved") {
                     let couponEvent = swiftApi.CouponEventModel()
                    SwiftEventBus.post("coupon_retrieved", sender: couponEvent)