[gdk-pixbuf] gdk-pixbuf-loader: Fix up previous commit 2634506c

[Philip Withnall <pwithnall src gnome org>]

commit 01f7543909dabff124ae2d4314a1c36f4307989a
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Feb 7 12:03:00 2017 +0000

    gdk-pixbuf-loader: Fix up previous commit 2634506c
    
    The assertion needs to be the target of an implication (count > 0), as
    it could legitimately be false if (count == 0).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776990

 gdk-pixbuf/gdk-pixbuf-loader.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk-pixbuf/gdk-pixbuf-loader.c b/gdk-pixbuf/gdk-pixbuf-loader.c
index 9f0fa79..89f46a3 100644
--- a/gdk-pixbuf/gdk-pixbuf-loader.c
+++ b/gdk-pixbuf/gdk-pixbuf-loader.c
@@ -517,7 +517,7 @@ gdk_pixbuf_loader_write (GdkPixbufLoader *loader,
                 }
   
         /* By this point, we expect the image_module to have been loaded. */
-        g_assert (priv->image_module != NULL);
+        g_assert (count == 0 || priv->image_module != NULL);
 
         if (count > 0 && priv->image_module->load_increment != NULL)
                 {