deltas: Make ostree_repo_static_delta_reindex() public

It is useful to be able to trigger this without having to regenerate
the summary. For example, if you are not using summaries, or ar generating
the summaries yourself.

src/libostree/ostree-repo-static-delta-core.c

@@ -1238,11 +1238,29 @@ file_has_content (OstreeRepo   *repo,
   return g_bytes_equal (existing_data, data);
 }
 
+/**
+ * ostree_repo_static_delta_reindex:
+ * @repo: Repo
+ * @flags: Flags affecting the indexing operation
+ * @opt_to_commit: ASCII SHA256 checksum of target commit, or %NULL to index all targets
+ * @cancellable: Cancellable
+ * @error: Error
+ *
+ * The delta index for a particular commit lists all the existing deltas that can be used
+ * when downloading that commit. This operation regenerates these indexes, either for
+ * a particular commit (if @opt_to_commit is non-%NULL), or for all commits that
+ * are reachable by an existing delta (if @opt_to_commit is %NULL).
+ *
+ * This is normally called automatically when the summary is updated in ostree_repo_regenerate_summary().
+ *
+ * Locking: shared
+ */
 gboolean
-_ostree_repo_static_delta_reindex (OstreeRepo                 *repo,
-                                   const char                 *opt_to_commit,
-                                   GCancellable               *cancellable,
-                                   GError                    **error)
+ostree_repo_static_delta_reindex (OstreeRepo                 *repo,
+                                  OstreeStaticDeltaIndexFlags flags,
+                                  const char                 *opt_to_commit,
+                                  GCancellable               *cancellable,
+                                  GError                    **error)
 {
   g_autoptr(GPtrArray) all_deltas = NULL;
   g_autoptr(GHashTable) deltas_to_commit_ht = NULL; /* map: to checksum -> ptrarray of from checksums (or NULL) */