$ vagrant --version
Ignoring ffi-1.9.14 because its extensions are not built. Try: gem pristine ffi --version 1.9.14
Ignoring nokogiri-1.6.7.1 because its extensions are not built. Try: gem pristine nokogiri --version 1.6.7.1
Ignoring unf_ext-0.0.7.2 because its extensions are not built. Try: gem pristine unf_ext --version 0.0.7.2
Vagrant 1.9.7