Report the actual host that failed to connect

Instead of the eventual target where our proxy chain will connect. In
the usual case (no Proxies set), this will be the same output as before.
When proxies are given, the user will see that the first proxy
connection is actually what failed.
Add tcp evasion options to mssql_login
Restore proxies to ssh scanners
Clean up exceptions

Of particular note is mysql, who was rescuing Rex::ConnectionTimeout
*after* Rex::ConnectionError, which never would have fired anyway.