reproducible: improve comments

hosts/jenkins/etc/pbuilder/rebuild-hooks/D01_modify_environment

@@ -2,11 +2,12 @@
 
 set -e
 
-# exit if we are in the same UTS namespace than init
+# exit if we are in the same UTS namespace as init ( != 2nd build )
 [ "$(readlink /proc/1/ns/uts)" = "$(readlink /proc/self/ns/uts)" ] && exit 0
 
-echo "I: Changing hostname to test build reproducibility" >&2
+echo "I: Changing host+domainname to test build reproducibility" >&2
 sed -e '/^127.0.0.1/s/$/ i-capture-the-hostname i-capture-the-hostname.i-capture-the-domain/' -i /etc/hosts
 hostname i-capture-the-hostname
 domainname i-capture-the-domain
+echo "I: Adding a custom variable just for the fun of it..." >&2
 export CAPTURE_ENVIRONMENT="I capture the environment"