(MAINT) Fix bug connecting to windows vagrant host

When running multiple hosts in vagrant with an linux master and windows
agent it seems that vagrant has difficulty connecting to box when the
ssh_config file contains 127.0.0.1 for the host. This change fixes the
issue by replacing it with the host ip if it has been specified in the
nodeset.

This might need a little more manual testing.
Merge pull request #421 from liamjbennett/vagrant_ssh_config

Fix bug connecting to windows vagrant host