[ostree] repo: Don't call g_hash_table_destroy on a NULL hash

[Colin Walters <walters src gnome org>]

commit 247e027125b4b56a9543042a382677aca81c78cc
Author: Colin Walters <walters verbum org>
Date:   Wed Nov 30 20:23:10 2011 -0500

    repo: Don't call g_hash_table_destroy on a NULL hash

 src/libostree/ostree-repo.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/libostree/ostree-repo.c b/src/libostree/ostree-repo.c
index 1ba6324..f87bd33 100644
--- a/src/libostree/ostree-repo.c
+++ b/src/libostree/ostree-repo.c
@@ -1197,9 +1197,12 @@ import_directory_recurse (OstreeRepo           *self,
   g_clear_object (&dir_enum);
   g_clear_object (&child);
   g_clear_object (&child_info);
-  g_hash_table_destroy (file_checksums);
-  g_hash_table_destroy (dir_metadata_checksums);
-  g_hash_table_destroy (dir_contents_checksums);
+  if (file_checksums)
+    g_hash_table_destroy (file_checksums);
+  if (dir_metadata_checksums)
+    g_hash_table_destroy (dir_metadata_checksums);
+  if (dir_contents_checksums)
+    g_hash_table_destroy (dir_contents_checksums);
   ot_clear_checksum (&ret_metadata_checksum);
   ot_clear_checksum (&ret_contents_checksum);
   ot_clear_checksum (&child_file_checksum);