adding required openstack libraries to requirements.txt

for testing purposes I have added a workstation entry
in vagrant so that you can spin up a precise box with all
the bits already set up including copying over your `~/.stackrc`
so that you can run `cd /vagrant; ./test/setup` immediately.

I have locked the versions of neutronclient and novaclient as
there are breaking changes in them.   There is a followup PR
that will fix those and alter the versions (pull/522) that I need to
rebase off this.