[libgit2-glib] Fix wrong return value

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 1cd26e77ecf146c7c808d384be18372fb34aa2a5
Author: Jesse van den Kieboom <jkieboom esri com>
Date:   Sun Nov 8 19:41:12 2015 +0100

    Fix wrong return value

 libgit2-glib/ggit-repository.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgit2-glib/ggit-repository.c b/libgit2-glib/ggit-repository.c
index 0e37039..d6fe385 100644
--- a/libgit2-glib/ggit-repository.c
+++ b/libgit2-glib/ggit-repository.c
@@ -927,7 +927,7 @@ ggit_repository_set_head (GgitRepository   *repository,
 
        g_return_val_if_fail (GGIT_IS_REPOSITORY (repository), FALSE);
        g_return_val_if_fail (ref_name != NULL, FALSE);
-       g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+       g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 
        ret = git_repository_set_head (_ggit_native_get (repository), ref_name);