removed check for omitNull

lib/associations/has-many-single-linked.js

@@ -22,7 +22,7 @@ module.exports = (function() {
 
     // clear the old associations
     oldAssociations.forEach(function(associatedObject) {
-      associatedObject[self.__factory.identifier] = /*options.omitNull ? '' :*/ null
+      associatedObject[self.__factory.identifier] = null
       chainer.add(associatedObject.save())
     })
 

lib/associations/has-one.js

@@ -54,7 +54,7 @@ module.exports = (function() {
       return new Utils.CustomEventEmitter(function(emitter) {
         obj[self.accessors.get]().success(function(oldObj) {
           if(oldObj) {
-            oldObj[self.identifier] = /*options.omitNull ? '' :*/ null;
+            oldObj[self.identifier] = null
             oldObj.save()
           }