Multiple nodes for openstack fails

[Denis Yuen]

The code for parsing floating ip addresses has been broken, it is no longer possible to specify ip addresses for multiple nodes in openstack. The closest we can get is to use os_floating_ip=10.5.74.150 to specify a floating ip address for one node, but multiple ip addresses are not broken up and instead get templated out to all Vagrant files incorrectly.

Also see #36