[ostree] diff: do not traverse parent commits

[Giuseppe Scrivano <gscrivano src gnome org>]

commit a13b56f91c898ac5c24ea587183d7e99dea3c4cb
Author: Giuseppe Scrivano <gscrivan redhat com>
Date:   Fri Jan 15 10:24:08 2016 +0100

    diff: do not traverse parent commits
    
    The object count displayed included also the number of parent
    commits.
    
    Signed-off-by: Giuseppe Scrivano <gscrivan redhat com>

 src/ostree/ot-builtin-diff.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/ostree/ot-builtin-diff.c b/src/ostree/ot-builtin-diff.c
index 2a27f5d..b5e0c5a 100644
--- a/src/ostree/ot-builtin-diff.c
+++ b/src/ostree/ot-builtin-diff.c
@@ -194,9 +194,9 @@ ostree_builtin_diff (int argc, char **argv, GCancellable *cancellable, GError **
       if (!ostree_repo_resolve_rev (repo, target, FALSE, &rev_b, error))
         goto out;
 
-      if (!ostree_repo_traverse_commit (repo, rev_a, -1, &reachable_a, cancellable, error))
+      if (!ostree_repo_traverse_commit (repo, rev_a, 0, &reachable_a, cancellable, error))
         goto out;
-      if (!ostree_repo_traverse_commit (repo, rev_b, -1, &reachable_b, cancellable, error))
+      if (!ostree_repo_traverse_commit (repo, rev_b, 0, &reachable_b, cancellable, error))
         goto out;
 
       a_size = g_hash_table_size (reachable_a);