Fix template to default typed input field

to close #1697

nodes/core/core/80-template.html

@@ -106,6 +106,10 @@
         },
         oneditprepare: function() {
             var that = this;
+            if (!this.field) {
+                this.field = 'payload';
+                $("#node-input-field").val("payload");
+            }
             if (!this.fieldType) {
                 this.fieldType = 'msg';
             }