Been meaning to do this for years: introduce a configuration option

to manually tweak the host name and port number under which the SSH
host key is read and written.

I've put it in the cross-platform Connection panel. Partly under the
flimsy pretext that other backends _can_ use it if they so wish (and
in fact it overrides the host name for title-bar purposes in all
network backends, though it has no other effect in anything but
SSH); but mostly because the SSH panel was too full already :-)

[originally from svn r8033]

putty.h

@@ -427,6 +427,7 @@ struct config_tag {
     int ping_interval;		       /* in seconds */
     int tcp_nodelay;
     int tcp_keepalives;
+    char loghost[512];  /* logical host being contacted, for host key check */
     /* Proxy options */
     char proxy_exclude_list[512];
     int proxy_dns;