libostree: Delete some leftover remnant API for archive files

src/libostree/ostree-repo-private.h

@@ -65,10 +65,6 @@ GFile *
 _ostree_repo_get_uncompressed_object_cache_path (OstreeRepo       *self,
                                                  const char       *checksum);
 
-GFile *
-_ostree_repo_get_archive_content_path (OstreeRepo    *self,
-                                       const char    *checksum);
-
 GFile *
 _ostree_repo_get_file_object_path (OstreeRepo   *self,
                                    const char   *checksum);