migration: reorder MIG_CMD_POSTCOPY_RESUME

It was accidently added before MIG_CMD_PACKAGED so it might break
command compatibility when we run postcopy migration between old/new
QEMUs.  Fix that up quickly before the QEMU 3.0 release.
Reported-by: NLukáš Doktor <ldoktor@redhat.com>
Suggested-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <20180710094424.30754-1-peterx@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

migration/savevm.c

@@ -81,8 +81,8 @@ enum qemu_vm_cmd {
     MIG_CMD_POSTCOPY_RAM_DISCARD,  /* A list of pages to discard that
                                       were previously sent during
                                       precopy but are dirty. */
-    MIG_CMD_POSTCOPY_RESUME,       /* resume postcopy on dest */
     MIG_CMD_PACKAGED,          /* Send a wrapped stream within this stream */
+    MIG_CMD_POSTCOPY_RESUME,   /* resume postcopy on dest */
     MIG_CMD_RECV_BITMAP,       /* Request for recved bitmap on dst */
     MIG_CMD_MAX
 };