tests/test-serve.out

hgweb: clarify which address and port can/cannot be bound at startup (bug 769)

The error message at startup when the address/port could not be bound
was confusing:

    hg serve
    abort: cannot start server: Address already in use

Be more explicit:

    $ hg serve -a localhost
    abort: cannot start server at 'localhost:8000': Address already in use

Also be more explicit on success, showing hostname and ip address/port:

    $ hg -v serve -a localhost -p 80
    listening at http://localhost/ (127.0.0.1:80)


We are careful to handle a missconfigured machine whose hostname does not
resolve, falling back to the address given at the command line.

Remove a dead-code error message.

% Without -v
access log created - .hg/hgrc respected
% With -v
listening at http://localhost/ (127.0.0.1)
% With --prefix foo
listening at http://localhost/foo/ (127.0.0.1)
% With --prefix /foo
listening at http://localhost/foo/ (127.0.0.1)
% With --prefix foo/
listening at http://localhost/foo/ (127.0.0.1)
% With --prefix /foo/
listening at http://localhost/foo/ (127.0.0.1)