[libgit2-glib] commit: remove useless assertion

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 9605a38f09f0db36cfa189ffb4122a77d59834bd
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Fri Aug 5 10:38:47 2016 +0200

    commit: remove useless assertion
    
    guint already ensures >= 0. This was discovered by codecoverage

 libgit2-glib/ggit-commit.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/libgit2-glib/ggit-commit.c b/libgit2-glib/ggit-commit.c
index 8b18582..173d12b 100644
--- a/libgit2-glib/ggit-commit.c
+++ b/libgit2-glib/ggit-commit.c
@@ -357,7 +357,6 @@ ggit_commit_get_nth_ancestor (GgitCommit  *commit,
        gint ret;
 
        g_return_val_if_fail (GGIT_IS_COMMIT (commit), NULL);
-       g_return_val_if_fail (n >= 0, NULL);
        g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 
        ret = git_commit_nth_gen_ancestor (&ancestor, _ggit_native_get (commit), n);