Declare the 'rdata' argument for dns_rdata_tostruct() to be const

(cherry picked from commit abb2fd10)
7 jobs for 341-constify-dns_rdata_tostruct-v9_12 in 8 minutes and 56 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Precheck
passed #18933
amd64 docker linux
precheck:debian:sid:amd64

00:00:11

 
  Build
passed #18934
amd64 docker linux
build:debian:sid:amd64

00:03:04

passed #18935
i386 docker linux
build:debian:sid:i386

00:03:16

 
  Test
passed #18938
amd64 docker linux
systemtest:debian:sid:amd64

00:04:45

passed #18939
i386 docker linux
systemtest:debian:sid:i386

00:05:26

passed #18936
amd64 docker linux
unittest:debian:sid:amd64

00:00:51

passed #18937
i386 docker linux
unittest:debian:sid:i386

00:00:51