Hotfix Update ParentNode FK Fail

Signed-off-by: Chaoscaot <chaoscaot444@gmail.com>

SpigotCore_Main/src/de/steamwar/sql/SchematicNode.java

@@ -94,6 +94,9 @@ public class SchematicNode {
         owner = set.getInt("NodeOwner");
         name = set.getString("NodeName");
         parent = set.getInt("ParentNode");
+        if(set.wasNull()) {
+            parent = null;
+        }
         item = set.getString("NodeItem");
         type = set.getString("NodeType");
         lastUpdate = set.getTimestamp("LastUpdate");
@@ -417,6 +420,7 @@ public class SchematicNode {
     }
 
     public SchematicNode getParentNode() {
+        if(parent == null) return null;
         return SchematicNode.getSchematicNode(parent);
     }