delete clone destination directory before cloning

Author: Vladimir Kotal

opengrok-indexer/src/test/java/org/opengrok/indexer/history/GitRepositoryTest.java

@@ -203,6 +203,7 @@ public void testDetermineParent() throws Exception {
         // Next, clone the repository and create new origin there.
         // Clone under source root to avoid problems with prohibited symlinks.
         File localPath = new File(repository.getSourceRoot(), "gitCloneTestDetermineBranch");
+        assertTrue(localPath.delete());
         String cloneUrl = root.toURI().toString();
         try (Git gitClone = Git.cloneRepository()
                 .setURI(cloneUrl)