[gegl] perf: fix compilation when doing retrospective builds

[Øyvind Kolås <ok src gnome org>]

commit 84bb663f6c6089d821bc5eca09875fb4a7d4d12d
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Jan 5 16:03:15 2018 +0100

    perf: fix compilation when doing retrospective builds

 perf/test-common.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/perf/test-common.h b/perf/test-common.h
index 5bc1195..fe478d0 100644
--- a/perf/test-common.h
+++ b/perf/test-common.h
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <glib.h>
 #include "gegl.h"
-#include "gegl/opencl/gegl-cl-init.h"
+#include "opencl/gegl-cl-init.h"
 
 static long ticks_start;