add $this->maxDepth to serialize / unserialize

src/JMS/Serializer/Metadata/VirtualPropertyMetadata.php

@@ -61,6 +61,7 @@ class VirtualPropertyMetadata extends PropertyMetadata
             $this->xmlKeyValuePairs,
             $this->xmlElementCData,
             $this->xmlAttributeMap,
+            $this->maxDepth,
             $this->getter,
             $this->setter,
             $this->inline,
@@ -88,6 +89,7 @@ class VirtualPropertyMetadata extends PropertyMetadata
             $this->xmlKeyValuePairs,
             $this->xmlElementCData,
             $this->xmlAttributeMap,
+            $this->maxDepth,
             $this->getter,
             $this->setter,
             $this->inline,