merge some minor changes from 1.5 branch

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273547 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -50,6 +50,9 @@ Fixed bugs:
 
 * <javadoc> will now pass -source to custom doclets as well.
 
+* <cvstagdiff> would throw a NullPointException if there had been no
+  differences.
+
 Other changes:
 --------------
 * <setproxy> lets you set the username and password for proxies that want authentication

docs/manual/CoreTasks/cvstagdiff.html

@@ -135,7 +135,10 @@ It writes these changes into the file <code>tagdiff.xml</code>.</p>
 <p>Generates a tagdiff report for all the changes that have been made
 in the <code>jakarta-ant</code> module in january 2002, with <code>rootdir</code> indicating that 
 the actual location of the <code>jakarta-ant</code> module in cvs is <code>jakarta/ant</code> 
-rather than <code>jakarta-ant</code>.
+rather than <code>jakarta-ant</code>. In this example <code>cvsRoot</code>
+has not been set. The current <code>cvsRoot</code> will be used (assuming the build is started
+from a folder stored in <code>cvs</code>.
+It writes these changes into the file <code>tagdiff.xml</code>.</p>
 
 <h4>Generate Report</h4>
 <p>Ant includes a basic XSLT stylesheet that you can use to generate 

src/main/org/apache/tools/ant/taskdefs/cvslib/CvsTagDiff.java

@@ -96,6 +96,7 @@ import org.apache.tools.ant.util.FileUtils;
  * </PRE>
  *
  * @author <a href="mailto:fred@castify.net">Frederic Lavigne</a>
+ * @author <a href="mailto:rvanoo@xs4all.nl">Rob van Oostrum</a>
  * @version $Revision$ $Date$
  * @since Ant 1.5
  * @ant.task name="cvstagdiff"