migration: Move qjson.h to migration/

It is only used for migration code.
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

migration/qjson.c

@@ -25,7 +25,7 @@
 
 #include "qemu/osdep.h"
 #include "qapi/qmp/qstring.h"
-#include "migration/qjson.h"
+#include "qjson.h"
 
 struct QJSON {
     QString *str;

migration/vmstate.c

@@ -7,7 +7,7 @@
 #include "qemu/error-report.h"
 #include "qemu/queue.h"
 #include "trace.h"
-#include "migration/qjson.h"
+#include "qjson.h"
 
 static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
                                     void *opaque, QJSON *vmdesc);