[gdk-pixbuf] Fix the new test to run as installed test

[Matthias Clasen <matthiasc src gnome org>]

commit b241c465fad3de320a487f859267f3677655985c
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jun 1 12:57:41 2016 -0400

    Fix the new test to run as installed test

 tests/pixbuf-composite.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/pixbuf-composite.c b/tests/pixbuf-composite.c
index 3bd201f..f6b5feb 100644
--- a/tests/pixbuf-composite.c
+++ b/tests/pixbuf-composite.c
@@ -64,7 +64,7 @@ test_composite2 (void)
   GdkPixbuf *src, *dest;
   guchar *pixels, *p;
 
-  src = gdk_pixbuf_new_from_file ("test-image.png", NULL);
+  src = gdk_pixbuf_new_from_file (g_test_get_filename (G_TEST_DIST, "test-image.png"), NULL);
 
   {
     GdkPixbuf *tmp = gdk_pixbuf_new (GDK_COLORSPACE_RGB,