RemotePeer configuration has suspicious handling of port

[DMRobertson]

The peers table is responsible for generating RemotePeer objetcs. RemotePeer is responsible for (amongst other things) working out which replication url to use.

• We'll use the port defined in the configuration url (possibly 443 implicitly)
• If there's no replication url configured, we'll use the port provided in the call to RemotePeer.__init__
  • If port is Falsey then use 1001; else use

After this, the only uses of port and self.port are for logging. We always log with %d, so expect this to be an integer.

There is a path here where you can do a bad thing.

1. Don't configure any base replication urls
2. Add an entry to peers with a NULL port
3. Every call to RemotePeer will try to format None as an integer, which will raise a TypeError.

>>> "%d" % None
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: %d format: a number is required, not NoneType

Equally, if we did specify a port in the DB and did provide a replication URL, the db's port would be ignored, but the logging would continue to print it anyway!

Fix this by logging the base replication url so we don't have any need for the port.