[dns64] allow any unique local IPv6 address (#226)
[dns64] allow any unique local IPv6 address (#226)


bukepo/borderrouter,jwhui/borderrouter,bukepo/borderrouter,openthread/borderrouter,openthread/borderrouter,openthread/ot-br-posix,openthread/borderrouter,jwhui/borderrouter,bukepo/borderrouter,openthread/ot-br-posix,jwhui/borderrouter,openthread/ot-br-posix,openthread/borderrouter,openthread/ot-br-posix,openthread/borderrouter,openthread/ot-br-posix,openthread/borderrouter,openthread/ot-br-posix,jwhui/borderrouter,jwhui/borderrouter,bukepo/borderrouter,bukepo/borderrouter