[gegl] png-load: Fix a compile warning

[Jon Nordby <jonnor src gnome org>]

commit 3577c01fb5f099cd25cfcaaada8e0adbc4558ff0
Author: Jon Nordby <jononor gmail com>
Date:   Mon Nov 10 16:24:56 2014 +0100

    png-load: Fix a compile warning

 operations/external/png-load.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/operations/external/png-load.c b/operations/external/png-load.c
index c623d01..b339370 100644
--- a/operations/external/png-load.c
+++ b/operations/external/png-load.c
@@ -421,7 +421,7 @@ get_bounding_box (GeglOperation *operation)
 
   GInputStream *stream = gegl_gio_open_input_stream(o->uri, o->path, &infile, &err);
   WARN_IF_ERROR(err);
-  if (!stream) return;
+  if (!stream) return result;
   status = query_png(stream, &width, &height, &format, &err);
   WARN_IF_ERROR(err);
   g_input_stream_close(stream, NULL, NULL);