Move migration.h to include/migration/

+ qemu_file.h -> include/migration/qemu-file.h
+ thunk.h -> include/exec/user/

Change-Id: I6fc339ac0fe9d366db1ed095dff08f5619ebc3d5
diff --git a/thunk.c b/thunk.c
index 0657188..579d1e8 100644
--- a/thunk.c
+++ b/thunk.c
@@ -21,7 +21,7 @@
 #include <stdarg.h>
 
 #include "qemu.h"
-#include "thunk.h"
+#include "exec/user/thunk.h"
 
 //#define DEBUG