Fix startup so that log prefix %h works for the log_connections message.
Fix startup so that log prefix %h works for the log_connections message.

We entirely randomly chose to initialize port->remote_host just after
printing the log_connections message, when we could perfectly well do it
just before, allowing %h and %r to work for that message.  Per gripe from
Artem Tomyuk.

zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl