Fix docstrings, add ex_admin_pass argument to create_node
in the Openstack driver.

Closes #315

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Merge branch 'trunk' of https://git-wip-us.apache.org/repos/asf/libcloud into trunk
Remove extra comma, re-order changes.
Fix a possible race condition in deploy_node which would occur if node
is online and can be accessed via SSH, but the SSH key we want to use hasn't
been installed yet.

Closes #331

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Include a better message in the exception which is thrown when a request
in the Rackspace driver ends up in an ERROR state.