migration: drop an unused include

In the vmstate.h file, we just need a struct name. Use a forward
declaration instead of an include, then adjust the one affected .c file
to include the file that is no longer implicit from the header.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

include/migration/vmstate.h

@@ -27,7 +27,7 @@
 #ifndef QEMU_VMSTATE_H
 #define QEMU_VMSTATE_H
 
-#include "migration/qjson.h"
+typedef struct QJSON QJSON;
 
 typedef struct VMStateInfo VMStateInfo;
 typedef struct VMStateDescription VMStateDescription;

migration/savevm.c

@@ -55,6 +55,7 @@
 #include "io/channel-buffer.h"
 #include "io/channel-file.h"
 #include "sysemu/replay.h"
+#include "qjson.h"
 
 #ifndef ETH_P_RARP
 #define ETH_P_RARP 0x8035