6951064: Typo in javadoc for ZipException ctors

Summary: fixed the doc typo
Reviewed-by: martin

src/share/classes/java/util/zip/ZipException.java

 /*
- * Copyright 1995-2008 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1995-2010 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ class ZipException extends IOException {
     private static final long serialVersionUID = 8000196834066748623L;
 
     /**
-     * Constructs an <code>ZipException</code> with <code>null</code>
+     * Constructs a <code>ZipException</code> with <code>null</code>
      * as its error detail message.
      */
     public ZipException() {
@@ -48,7 +48,7 @@ class ZipException extends IOException {
     }
 
     /**
-     * Constructs an <code>ZipException</code> with the specified detail
+     * Constructs a <code>ZipException</code> with the specified detail
      * message.
      *
      * @param   s   the detail message.