using JDK 1.6 on Windows D:\ has a valid canonical path even if the drive is not ready

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@918096 13f79535-47bb-0310-9956-ffa450edef68

src/tests/junit/org/apache/tools/ant/taskdefs/ManifestClassPathTest.java

@@ -168,7 +168,7 @@ public class ManifestClassPathTest
             System.out.println("Test with drive letters only run on windows");
         } else {
             try {
-                new java.io.File("D:/").getCanonicalPath();
+                new java.io.File("D:/foo.txt").getCanonicalPath();
             } catch (java.io.IOException e) {
                 System.out.println("drive d: doesn't exist or is not ready,"
                                    + " skipping test");