libostree: Fix bracket-missing warnings

Apparently I got the bracketing wrong in
862e6ecdcc:

src/libostree/ostree-repo.c: In function 'ostree_repo_delete_object':
src/libostree/ostree-repo.c:3538:11: warning: missing braces around
initializer [-Wmissing-braces]
           g_auto(GVariantBuilder) builder = {0,};

Closes: #298
Approved by: cgwalters

src/libostree/ostree-repo.c

@@ -3510,7 +3510,7 @@ ostree_repo_delete_object (OstreeRepo           *self,
 
       if (tombstone_commits)
         {
-          g_auto(GVariantBuilder) builder = {0,};
+          g_auto(GVariantBuilder) builder = {{0,}};
           g_autoptr(GVariant) variant = NULL;
 
           g_variant_builder_init (&builder, G_VARIANT_TYPE ("a{sv}"));
@@ -4956,7 +4956,7 @@ ostree_repo_regenerate_summary (OstreeRepo     *self,
   g_autoptr(GVariant) summary = NULL;
   GList *ordered_keys = NULL;
   GList *iter = NULL;
-  g_auto(GVariantDict) additional_metadata_builder = {0,};
+  g_auto(GVariantDict) additional_metadata_builder = {{0,}};
 
   if (!ostree_repo_list_refs (self, NULL, &refs, cancellable, error))
     goto out;
@@ -4989,7 +4989,7 @@ ostree_repo_regenerate_summary (OstreeRepo     *self,
   {
     guint i;
     g_autoptr(GPtrArray) delta_names = NULL;
-    g_auto(GVariantDict) deltas_builder = {0,};
+    g_auto(GVariantDict) deltas_builder = {{0,}};
     g_autoptr(GVariant) deltas = NULL;
 
     if (!ostree_repo_list_static_delta_names (self, &delta_names, cancellable, error))