remove last impl. dependency from api

I noticed the following by accident:

/* Copyright 2014--2015 The Tor Project
 * See LICENSE for licensing information */
package org.torproject.descriptor;

@SuppressWarnings("deprecation")
public class DescriptorParseException
    extends org.torproject.descriptor.impl.DescriptorParseException {
//     api extends implementation?   ^^^^^^
  private static final long serialVersionUID = 100L;
  public DescriptorParseException(String message) {
    super(message);
  }
}

Shouldn't it be changed? e.g.

diff --git a/src/org/torproject/descriptor/DescriptorParseException.java b/src/org/torproject/descriptor/DescriptorParseException.java
index ff5707d..f2f18f8 100644
--- a/src/org/torproject/descriptor/DescriptorParseException.java
+++ b/src/org/torproject/descriptor/DescriptorParseException.java
@@ -2,9 +2,7 @@
  * See LICENSE for licensing information */
 package org.torproject.descriptor;
 
-@SuppressWarnings("deprecation")
-public class DescriptorParseException
-    extends org.torproject.descriptor.impl.DescriptorParseException {
+public class DescriptorParseException extends Exception {
   private static final long serialVersionUID = 100L;
   public DescriptorParseException(String message) {
     super(message);
diff --git a/src/org/torproject/descriptor/impl/DescriptorParseException.java b/src/org/torproject/descriptor/impl/DescriptorParseException.java
deleted file mode 100644
index 0f9add2..0000000
--- a/src/org/torproject/descriptor/impl/DescriptorParseException.java
+++ /dev/null
@@ -1,15 +0,0 @@
-/* Copyright 2011--2015 The Tor Project
- * See LICENSE for licensing information */
-package org.torproject.descriptor.impl;
-
-/**
- * @deprecated Replaced by
- * org.torproject.descriptor.DescriptorParseException
- */
-@Deprecated public class DescriptorParseException extends Exception {
-  private static final long serialVersionUID = 100L;
-  protected DescriptorParseException(String message) {
-    super(message);
-  }
-}
-

The above compiles fine; was there a particular reason for extending the implementation exception or did we just miss this?