xfrm: make state as DEAD before final put when migrate fails

xfrm: make state as DEAD before final put when migrate fails

xfrm_state_migrate/xfrm_state_clone_and_setup create a new state, and
call xfrm_state_put to destroy it in case of
failure. __xfrm_state_destroy expects the state to be in
XFRM_STATE_DEAD, but we currently don't do that.

Reported-by: syzbot+5cd6299ede4d4f70987b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=5cd6299ede4d4f70987b
Fixes: 78347c8c6b2d ("xfrm: Fix xfrm_state_migrate leak")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>