caja-directory.c: Fix memory leak.

When creating a new file (using a template, for instance), file->
details->is_added could potentially be FALSE, and cause this file to
not be finalized along with other files if the view directory is
destroyed.

This can cause issues when re-entering that directory, with the file
being in an undefined state, and could prevent the view from fully
loading the location (this is identical behavior to that described
in mate-desktop/python-caja#64.

To reproduce:
- Create an svg file and save in ~/Templates.
- Right-click, Create document-> svg file, name it whatever.
- Navigate out of the folder.
- Modify the file in a visible manner.
- Re-enter the folder, note that it never finishes loading.

Ref:
linuxmint/nemo#2736

libcaja-private/caja-directory.c

@@ -923,14 +923,14 @@ caja_directory_notify_files_added (GList *files)
              * If it was renamed this could be ignored, but
              * queue a change just in case */
             caja_file_changed (file);
-            caja_file_unref (file);
         }
         else
         {
             hash_table_list_prepend (added_lists,
                                      directory,
                                      g_object_ref (location));
         }
+        caja_file_unref (file);
         caja_directory_unref (directory);
     }