use pack to construct the reply as Net::DNS just get it wrong

(cherry picked from commit feaf381a)
14 jobs for 510-resolver-test-was-failing-v9_11 in 8 minutes and 29 seconds (queued for 1 second)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #51992
amd64 docker linux

00:00:16

 
  Build
passed build:centos:centos6:amd64 #51993
amd64 docker linux

00:03:18

passed build:centos:centos7:amd64 #51994
amd64 docker linux

00:03:32

passed build:debian:sid:amd64 #51995
amd64 docker linux

00:01:19

passed build:debian:sid:i386 #51996
i386 docker linux

00:01:27

 
  Test
passed install:debian:sid:amd64 #52005
amd64 docker linux

00:02:27

passed systemtest:centos:centos6:amd64 #52001
amd64 docker linux

00:04:39

passed systemtest:centos:centos7:amd64 #52002
amd64 docker linux

00:04:39

passed systemtest:debian:sid:amd64 #52003
amd64 docker linux

00:04:20

passed systemtest:debian:sid:i386 #52004
i386 docker linux

00:04:23

passed unittest:centos:centos6:amd64 #51997
amd64 docker linux

00:01:11

passed unittest:centos:centos7:amd64 #51998
amd64 docker linux

00:01:13

passed unittest:debian:sid:amd64 #51999
amd64 docker linux

00:01:08

passed unittest:debian:sid:i386 #52000
i386 docker linux

00:01:00