[MERGE][RFC] Point out bzr+ssh:// to the user when they use ssh://.

[Stephen J. Turnbull]

Martin Pool writes:
 > 2009/2/18 Jelmer Vernooij <jelmer at samba.org>:

 > > Personally, I think registering ssh:// is a bad idea for a couple of reasons:
 > >
 > > * ssh:// just seems wrong semantically - bzr doesn't talk the ssh
 > > protocol; it talks the bzr protocol *tunneled over ssh*.

The scheme doesn't indicate the semantics of the content, it indicates
the syntax and semantics of the URL.  So you need to use "bzr+" (which
actually is an RFC violation, unfortunately) only if bzr would
interpret the URL differently from an ssh URL, and find a different
resource.

For example, in Mercurial http://authority//path is an error, while
hg://authority/path and hg://authority//path have different meanings
(the first is relative to the user's remote $HOME, the second is
absolute).  Default ports are different, I believe, too.  Those are
the kinds of issues that warrant a different scheme; tunneling does
not.