Fix #70

Author: hissy

src/PortlandLabs/Concrete5/MigrationTool/Importer/CIF/Element/Stack.php

@@ -53,6 +53,7 @@ public function getObjectCollection(\SimpleXMLElement $element, Batch $batch)
         if ($element->stacks) {
             $position = 0;
             foreach ($element->stacks->children() as $node) {
+                $blocks = null;
                 $stack = $this->parseStack($node);
                 $stack->setPosition($position);
                 if (isset($node->area->blocks->block)) {