kerndat: include config.h before using CONFIG_* contants

Otherwise someone can include kerndat.h before config.h
and get another kerndat structure. For example, proc_parse
doesn't include config.h and Cyrill met this problem.

Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/include/kerndat.h

@@ -4,6 +4,7 @@
 #include <stdbool.h>
 
 #include "int.h"
+#include "config.h"
 
 struct stat;