Adjust max recursion nesting

Otherwise this still triggered StackOverflow on some version of JDK

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1912403 13f79535-47bb-0310-9956-ffa450edef68

poi-scratchpad/src/main/java/org/apache/poi/hwpf/converter/WordToTextConverter.java

@@ -54,7 +54,7 @@ import org.w3c.dom.Element;
 public class WordToTextConverter extends AbstractWordConverter {
     private static final Logger LOG = LogManager.getLogger(WordToTextConverter.class);
 
-    private static final int MAX_NESTED_CHILD_NODES = 500;
+    private static final int MAX_NESTED_CHILD_NODES = 400;
 
     public static String getText( DirectoryNode root ) throws Exception
     {