caps: gst_caps_is_any() should return TRUE or FALSE

Not some flag value instead of TRUE. Fixes code like
gst_caps_is_any() == TRUE.

https://bugzilla.gnome.org//show_bug.cgi?id=731704

gst/gstcaps.c

@@ -92,7 +92,7 @@ typedef struct _GstCapsImpl
 
 /* same as gst_caps_is_any () */
 #define CAPS_IS_ANY(caps)				\
-  (GST_CAPS_FLAGS(caps) & GST_CAPS_FLAG_ANY)
+  (!!(GST_CAPS_FLAGS(caps) & GST_CAPS_FLAG_ANY))
 
 /* same as gst_caps_is_empty () */
 #define CAPS_IS_EMPTY(caps)				\