unit1650: fix out of boundary access

      rc = doh_decode((unsigned char *)full49, sizeof(full49)-1,

                      DNS_TYPE_A, &d);

      fail_if(d.numaddr != 1, "missing address");

      a = &d.addr[i];

      snprintf((char *)buffer, sizeof(buffer), "%d.%d.%d.%d\n",

      a = &d.addr[0];

      snprintf((char *)buffer, sizeof(buffer), "%d.%d.%d.%d",

               a->ip.v4 & 0xff, (a->ip.v4>>8) & 0xff,

               (a->ip.v4>>16) & 0xff, a->ip.v4 >>24);

      if(rc && strcmp((char *)buffer, "127.0.0.1")) {

        fprintf(stderr, "bad address decoded\n");

      if(rc || strcmp((char *)buffer, "127.0.0.1")) {

        fprintf(stderr, "bad address decoded: %s, rc == %d\n", buffer, rc);

        return 7;

      }

      fail_if(d.numcname, "bad cname counter");