extra-data: Simplify extra-data progress setup

We need to get the commit object to setup the extra-data progress information,
and this is currently done using a complex pull operation to a temporary
repo. According to https://github.com/flatpak/flatpak/issues/3515 it
even causes an unecessary download of the summary in some cases.

Now that we don't need to support p2p we can instead directly download
the commit object using a simple http operation (or from the sideload
repos), as we know the commit id at this point anyway.

common/flatpak-dir.c

@@ -4611,40 +4611,11 @@ flatpak_dir_setup_extra_data (FlatpakDir                           *self,
   /* ostree-metadata and appstreams never have extra data, so ignore those */
   if (g_str_has_prefix (ref, "app/") || g_str_has_prefix (ref, "runtime/"))
     {
-      extra_data_sources = flatpak_repo_get_extra_data_sources (repo, rev, cancellable, NULL);
+      g_autoptr(GVariant) commitv = flatpak_remote_state_load_ref_commit (state, self, ref, rev, error);
-      if (extra_data_sources == NULL)
+      if (commitv == NULL)
-        {
+        return FALSE;
-          /* This is a gigantic hack where we download the commit in a temporary transaction
-           * which we then abort after having read the result. We do this to avoid creating
-           * a partial commit in the local repo and a ref that points to it, because that
-           * causes ostree to not use static deltas.
-           * See https://github.com/flatpak/flatpak/issues/3412 for details.
-           */
 
-          if (!ostree_repo_prepare_transaction (repo, NULL, cancellable, error))
+      extra_data_sources = flatpak_commit_get_extra_data_sources (commitv, NULL);
-            return FALSE;
-
-          /* Pull the commits (and only the commits) to check for extra data
-           * again. Here we don't pass the progress because we don't want any
-           * reports coming out of it. */
-          if (!repo_pull (repo, state,
-                          NULL,
-                          ref,
-                          rev,
-                          sideload_repo,
-                          token,
-                          flatpak_flags,
-                          OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY,
-                          NULL,
-                          cancellable,
-                          error))
-            return FALSE;
-
-          extra_data_sources = flatpak_repo_get_extra_data_sources (repo, rev, cancellable, NULL);
-
-          if (!ostree_repo_abort_transaction (repo, cancellable, error))
-            return FALSE;
-        }
     }
 
   n_extra_data = 0;