Wrong level File object for successful delete.

Because the File object passed to the deleteGitRepository() routine was
parent instead of the respository to be deleted, the move and delete
would usually simply fail to happen.  Untested, but it could have been
a VERY serious problem with git repos that were not directly under the
git root, as the code would wind up deleting the parent instead of the
target repo, which could delete multiple repos if there were siblings at
2nd or lower levels.

Problem was introduced in change
bc4834c0eac09a97c271fda0b1e006426d8bc135

Change-Id: I0b0859d59bde2d8eaba681a6d68d2d2ceeacf84c
diff --git a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/FilesystemDeleteHandler.java b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/FilesystemDeleteHandler.java
index bbd68b5..8e381d5 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/FilesystemDeleteHandler.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/FilesystemDeleteHandler.java
@@ -73,10 +73,10 @@
     // Remove from the jgit cache
     Repository repository =
         repoManager.openRepository(project.getNameKey());
-    File repoParentFile = repository.getDirectory().getParentFile();
+    File repoFile = repository.getDirectory();
     cleanCache(repository);
     if (!preserveGitRepository) {
-      deleteGitRepository(project.getNameKey(), repoParentFile);
+      deleteGitRepository(project.getNameKey(), repoFile);
     }
   }
 
@@ -107,9 +107,9 @@
   }
 
   private void deleteGitRepository(final Project.NameKey project,
-      final File repoParentFile) throws IOException {
+      final File repoFile) throws IOException {
     // Delete the repository from disk
-    Path trash = moveToTrash(repoParentFile.toPath(), project);
+    Path trash = moveToTrash(repoFile.toPath(), project);
     try {
       recursiveDelete(trash);
     } catch (IOException e) {
@@ -119,7 +119,7 @@
     }
 
     // Delete parent folders if they are (now) empty
-    recursiveDeleteParent(repoParentFile, gitDir);
+    recursiveDeleteParent(repoFile.getParentFile(), gitDir);
 
     // Send an event that the repository was deleted
     ProjectDeletedListener.Event event = new ProjectDeletedListener.Event() {