fix(associations/hasOne): hasOne.createAssociation should use create directly (i…

…nstead of a create + set call), fixes #2304

lib/associations/has-one.js

@@ -143,17 +143,13 @@ module.exports = (function() {
   HasOne.prototype.injectCreator = function(instancePrototype) {
     var association = this;
 
-    instancePrototype[this.accessors.create] = function(values, fieldsOrOptions) {
-      var instance = this
-        , options = {};
-
-      if ((fieldsOrOptions || {}).transaction instanceof Transaction) {
-        options.transaction = fieldsOrOptions.transaction;
-      }
+    instancePrototype[this.accessors.create] = function(values, options) {
+      var instance = this;
+      options = options || {};
 
-      return association.target.create(values, fieldsOrOptions).then(function(associationInstance) {
-        return instance[association.accessors.set](associationInstance, options);
-      });
+      values[association.identifier] = instance.get(association.sourceIdentifier);
+      if (options.fields) options.fields.push(association.identifier);
+      return association.target.create(values, options);
     };
 
     return this;