Openstack cloud network, security group, floating IP filtering based on selected tenant

https://bugzilla.redhat.com/show_bug.cgi?id=1142487

Filter configuration items based on selected tenant, if the tenant is not selected it uses the provider to list all the configuration items.
@mkanoor I would like to see this broken down into further contexts so we do not have to setup all these objects for each test when most will not be used.  It would be better to setup the cloud tenants here and create the clould_networks, security_groups and floating_ips in separate contexts as needed.