Fixed used server connection credentials (also fixes 1.9 tests)

Fixes bug which makes use of servers with custom ssh port / user impossible.

I spent several hours messing with ssh server logs, before finally figure out who is a bad boy 

You owe me serveral hours of life :trollface: 

See #288

UPD:

How to reproduce:

```ruby
srv = ["ruby@some1.host:1122", "deploy@some2.host:1222" ]
role :app, *srv

```