Fixed what looks like a typo in the error message.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@268062 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Copy.java

@@ -203,8 +203,8 @@ public class Copy extends Task {
             throw new BuildException("One of destfile or destdir must be set.");
         }
 
-        if (file != null && destFile != null && file.exists() && file.isDirectory()) {
-            throw new BuildException("Use the dir attribute to copy directories.");
+        if (file != null && file.exists() && file.isDirectory()) {
+            throw new BuildException("Use a fileset to copy directories.");
         }
 
         if (destFile != null && filesets.size() > 0) {