Skip a test that cannot be verified on Windows

Change-Id: I1d1ed122c714f39ca7fb557224756205274804eb

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitAndLogCommandTests.java

@@ -256,6 +256,8 @@ public class CommitAndLogCommandTests extends RepositoryTestCase {
 
 	@Test
 	public void testModeChange() throws IOException, GitAPIException {
+		if (System.getProperty("os.name").startsWith("Windows"))
+			return; // SKIP
 		Git git = new Git(db);
 
 		// create file