Fix Vagrantfile after adding test suite.
Fix Vagrantfile after adding test suite.

The install_salt.sh script was moved, so use the new name,
and filter out the 'test' node when making the list of VMs.

UK992/saltfs,rwaweber/saltfs,setupminimal/saltfs,ALikhachev/saltfs,rwaweber/saltfs,UK992/saltfs,servo/saltfs,setupminimal/saltfs,ALikhachev/saltfs,servo/saltfs,setupminimal/saltfs,ALikhachev/saltfs,UK992/saltfs,rwaweber/saltfs