Remove unnecessary string formatting for sshCommand

[asgorobets]

Overview

This pull request:

• Fixes a bug
• Adds a feature
• Breaks backwards compatibility
• Has tests that cover changes

Summary

SshCommand is using sprintf to return a formatted command, but it's not actually sing any variables and basically just relies on inline variable interpolation. I think it is redundant and it's creating some other issues with string formatting, as now you have to escape your % characters in your options.

Description

Please see the following usage scenario:

$this->taskSshExec('company.com', 'user')
  ->option('-o', 'ProxyCommand ssh -A -q user@bastion.company.com nc %h %p');

If you use sprintf, you will have to escape all % chars with another %. But since sprintf is not doing any formatting now, I propose to replace it with string interpolation.

Possible breaking change:
This may be a breaking change for someone who already relied on sshCommand and was already escaping the '%' character, they may end up with %% in their custom code

[greg-1-anderson]

Well, this is definitely an improvement.

@DavertMik, any opinion on the b/c break?