[PATCH] Add user-dependent IdentityFile to OpenSSH-3.0.2p1

[Dan Kaminsky]

> IdentityFile now accepts the same %u, %h, %% options that
> AuthorizedKeysFile accepts (see man sshd). For example, one can specify a
> user-dependent IdentityFile in ssh_config:
>
> IdentityFile /ssh/%u/id_rsa

I like this, but if we're going to be supporting % variables, I'd like to
see them supported generically a la Samba.  ProxyCommand supports %h and %p,
for example, and it starts getting unweildy to mark which substittues what.
Perhaps throw a unified parser into readconf.c/ssh.c?

That being said, it's really, really useful to have access to % variables.

--Dan