Reverts access modifier change

Author: egalpin

src/main/java/com/fasterxml/jackson/core/JsonPointer.java

@@ -76,13 +76,13 @@ public class JsonPointer implements Serializable
     /* Construction
     /**********************************************************
      */
-    
+
     /**
      * Constructor used for creating "empty" instance, used to represent
      * state that matches current node. Note that this constructor must be public for
      * implementing {@link Externalizable}.
      */
-    public JsonPointer() {
+    protected JsonPointer() {
         _nextSegment = null;
         _matchingPropertyName = "";
         _matchingElementIndex = -1;