Replace the XmlRpcPlugin

[fhd]

Background

#3676 adds two Trac plugins:

1. The ​XmlRpc plugin.
2. The ​HttpAuth plugin, which allows the API user to authenticate via HTTP basic auth, interfacing with the ​AccountManager plugin we also use.

It would be better for security and sanity to not rely on these plugins.

What to change

Since we only need the Trac API for communicating between servers controlled by us, we could simply invoke a Python script via SSH that interacts with the Trac environment in the same way plugins do.

Since we don't want the change the issue status, it should be possible to minify the ​update code in XML-RPC plugin as follows:

from trac.env import Environment
from trac.util.datefmt import to_datetime, utc
import trac.ticket.model as model
from trac.ticket.notification import TicketNotifyEmail

env = Environment(env_path)
when = to_datetime(None, utc)
ticket = model.Ticket(env, ticket_id)
ticket.save_changes(author, comment, when=when)

try:
  tn = TicketNotifyEmail(env)
  tn.notify(ticket, newticket=False, modtime=when)
except Exception, e:
  warn("Failure sending notification on change of "
       "ticket #%s: %s" % (ticket.id, e))