b97778a6ea
Allow the from email address to be a ParameterizedString that
handles the ${userHash} variable. The value of the variable is
the md5 hash of the user name. This allows unique generation of
email addresses, so GMAIL threads names of users in conversations
correctly. For example, the from pattern for gerrit-review will be
of the form:
"${user} <noreply-gerritcodereview+${userHash}@google.com>"
Change-Id: I1bd649a9912e0a8f042b2130fbd694f2106468e8