[gegl] gegl:load use a formatting string for g_warning

[Øyvind Kolås <ok src gnome org>]

commit b325f27e2d31bed65ee4ba6bf440ca012a2ea9af
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Jun 4 15:42:29 2016 +0200

    gegl:load use a formatting string for g_warning

 operations/core/load.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/operations/core/load.c b/operations/core/load.c
index c279c12..7351f9e 100644
--- a/operations/core/load.c
+++ b/operations/core/load.c
@@ -168,7 +168,7 @@ do_setup (GeglOperation *operation, const gchar *path, const gchar *uri)
 
   if (!read_from_stream (stream, &buffer, &size, &error))
     {
-      g_warning (error->message);
+      g_warning ("%s", error->message);
       g_clear_error (&error);
       goto cleanup;
     }