migration: include qemu-file.h

They don't use/know anything about buffered-file.

Signed-off-by: Juan Quintela <quintela@redhat.com>
diff --git a/migration-unix.c b/migration-unix.c
index d5f9868..f2f368c 100644
--- a/migration-unix.c
+++ b/migration-unix.c
@@ -16,7 +16,7 @@
 #include "qemu-common.h"
 #include "qemu/sockets.h"
 #include "migration/migration.h"
-#include "buffered_file.h"
+#include "migration/qemu-file.h"
 #include "block/block.h"
 
 //#define DEBUG_MIGRATION_UNIX