This script will be run after sending the email to allow
acting upon the send result. The MimeMessage variable
is "msg," the SMTPTransport "transport," the session
properties "props," the build is also available as "build"
and a logger is available as "logger." The trigger that
caused the email is available as "trigger" and all triggered
builds are available as a map "triggered."
You can set the default post-send script here and then use
${DEFAULT_POSTSEND_SCRIPT} in the project settings to use
the script written here.