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/arch_init.c b/arch_init.c
index eaeb15f..48ab692 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -37,7 +37,7 @@
 #include "hw/pci.h"
 #include "hw/audiodev.h"
 #include "kvm.h"
-#include "migration.h"
+#include "migration/migration.h"
 #include "net/net.h"
 #include "exec/gdbstub.h"
 #include "hw/smbios.h"