[libgit2-glib] ggit-blob-output-stream.c: Fix return annotations

[Igor Gnatenko <ignatenko src gnome org>]

commit 00def6c14140c27fdb5711ab8e82cfe3f0851420
Author: Brian C. Lane <bcl redhat com>
Date:   Wed Aug 30 15:38:12 2017 -0700

    ggit-blob-output-stream.c: Fix return annotations
    
    Add (nullable) as needed.

 libgit2-glib/ggit-blob-output-stream.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgit2-glib/ggit-blob-output-stream.c b/libgit2-glib/ggit-blob-output-stream.c
index 9027ff8..c536cfd 100644
--- a/libgit2-glib/ggit-blob-output-stream.c
+++ b/libgit2-glib/ggit-blob-output-stream.c
@@ -286,7 +286,7 @@ _ggit_blob_output_stream_new (GgitRepository  *repository)
  * stream has been properly closed. If an error occurred while writing the blob,
  * the %NULL is returned and @error is set accordingly.
  *
- * Returns: (transfer full): a #GgitOId or %NULL.
+ * Returns: (transfer full) (nullable): a #GgitOId or %NULL.
  *
  **/
 GgitOId *