Revert "change manifest test appdir to subdir of tmpdir"

This reverts commit 9dabf9df.

test/test_manifest.rb

@@ -21,16 +21,14 @@ description: |
 documentation: |
   Links to support docs should go here.
 )
-    @tmpdir = Pathname.new File.realpath Dir.mktmpdir
-    @appdir = @tmpdir.join("cfs")
+    @appdir = Pathname.new File.realpath Dir.mktmpdir
     @yaml_path = @appdir.join("manifest.yml")
 
-    @appdir.mkpath
     File.open(@yaml_path, "w") { |f| f.write @yaml }
   end
 
   def teardown
-    FileUtils.remove_entry @tmpdir
+    FileUtils.remove_entry @appdir
   end
 
   def assert_valid_manifest(manifest)