FIX chef dependency problem,

I tried to intall vcap following the instructions on the README and I got this error:

> Installing chef...
> false
> ERROR:  Error installing chef:
>	net-ssh-gateway requires net-ssh (>= 2.6.5, runtime)

This is because New versions of net-ssh-multi and net-ssh-gateway depend on
net-ssh >= 2.6.4 which breaks chef's dependency on net-ssh ~> 2.2.2.

So, until the chef dependency problem will be fixed we can install net-ssh and net-ssh-gateway before chef and the problem is solved.

Thanks.