Fix mercurial build by ssh connection

[mubarakzyanov]

Contribution Type: bug fix Link to Intent to Implement: - Link to Bug: -

This pull request affects the following areas:

• [ ] Front-End
• [x] Builder
• [ ] Build Plugins

In raising this pull request, I confirm the following (please check boxes):

• [x] I have read and understood the contributing guidelines?
• [x] I have checked that another pull request for this purpose does not exist.
• [x] I have considered, and confirmed that this submission will be valuable to others.
• [x] I have created or updated the relevant documentation for this change on the PHPCI Wiki.
• [x] Do the PHPCI tests pass?

Detailed description of change:

Fix clone by ssh method for mercurial build