Fix OpenStack external tests

On OpenStack Folsom we cannot take a snapshot of a volume that
is attached to a server. On OpenStack Grizzly this has been fixed.
So we take the snapshot once the volume has been deattached from
the server.
Merge pull request #142 from cloudfoundry/openstack_snapshots

Fix OpenStack external tests
[spec] clean up formatting of cli_spec
[rspec] use unix redirection instead of rspec --out
[spec] agent should use a random smtp port when running specs
[aws plugin] attaching an EIP can take longer than we expected
[agent] functional test should show agent out/err on failure