[cheese] Avoid a preprocessor warning

[David King <davidk src gnome org>]

commit 8ff1b22ad51e8237838a27e26a908b60726a2f24
Author: David King <amigadave amigadave com>
Date:   Thu Jan 29 13:07:10 2015 +0000

    Avoid a preprocessor warning

 libcheese/cheese-camera.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/libcheese/cheese-camera.c b/libcheese/cheese-camera.c
index e260ff0..a98ef16 100644
--- a/libcheese/cheese-camera.c
+++ b/libcheese/cheese-camera.c
@@ -31,6 +31,8 @@
 #include <clutter/clutter.h>
 #include <clutter-gst/clutter-gst.h>
 #include <gst/gst.h>
+/* Avoid a warning. */
+#define GST_USE_UNSTABLE_API
 #include <gst/basecamerabinsrc/gstcamerabin-enum.h>
 #include <gst/pbutils/encoding-profile.h>
 #include <X11/Xlib.h>