(js) Avoid saving an empty calendar name

UI/WebServerResources/js/Contacts/AddressBooksController.js

@@ -106,6 +106,9 @@
           this.editMode = false;
         }
       }
+      else {
+        this.revertEditing(folder);
+      }
     };
 
     this.confirmDelete = function () {

UI/WebServerResources/js/Scheduler/sgCalendarListItem.directive.js

@@ -107,6 +107,9 @@
       if (this.inputElement.disabled)
         return;
 
+      if (this.inputElement.value.length === 0)
+        this.revertEditing();
+
       this.calendar.name = this.inputElement.value;
       this.inputElement.disabled = true;
       this.calendar.$rename()