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_12 in 7 minutes and 30 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #51978
amd64 docker linux

00:00:19

 
  Build
passed build:centos:centos6:amd64 #51979
amd64 docker linux

00:02:05

passed build:centos:centos7:amd64 #51980
amd64 docker linux

00:02:13

passed build:debian:sid:amd64 #51981
amd64 docker linux

00:01:34

passed build:debian:sid:i386 #51982
i386 docker linux

00:01:37

 
  Test
passed install:debian:sid:amd64 #51991
amd64 docker linux

00:02:45

passed systemtest:centos:centos6:amd64 #51987
amd64 docker linux

00:04:48

passed systemtest:centos:centos7:amd64 #51988
amd64 docker linux

00:04:48

passed systemtest:debian:sid:amd64 #51989
amd64 docker linux

00:04:41

passed systemtest:debian:sid:i386 #51990
i386 docker linux

00:04:56

passed unittest:centos:centos6:amd64 #51983
amd64 docker linux

00:01:06

passed unittest:centos:centos7:amd64 #51984
amd64 docker linux

00:01:05

passed unittest:debian:sid:amd64 #51985
amd64 docker linux

00:00:59

passed unittest:debian:sid:i386 #51986
i386 docker linux

00:01:00