[ostree] commit: Add missing (allow-none) in write_ref_immediate()

[Colin Walters <walters src gnome org>]

commit d750e2e2ebe8cb577dda6ad46126c63e6cf188b0
Author: Colin Walters <walters verbum org>
Date:   Tue Mar 3 21:16:33 2015 -0500

    commit: Add missing (allow-none) in write_ref_immediate()
    
    Spotted by Adam Coldrick.

 src/libostree/ostree-repo-commit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/libostree/ostree-repo-commit.c b/src/libostree/ostree-repo-commit.c
index 91b345e..8ea7d76 100644
--- a/src/libostree/ostree-repo-commit.c
+++ b/src/libostree/ostree-repo-commit.c
@@ -1302,7 +1302,7 @@ ostree_repo_transaction_set_ref (OstreeRepo *self,
  * @self: An #OstreeRepo
  * @remote: (allow-none): A remote for the ref
  * @ref: The ref to write
- * @checksum: The checksum to point it to
+ * @checksum: (allow-none): The checksum to point it to, or %NULL to unset
  * @cancellable: GCancellable
  * @error: GError
  *