Add missing schema definitions

Vcloud::Core::OrgVdcNetwork.provision handles :description, :is_shared,
and :dns_suffix options. These were omitted from the net_launch schema however,
so vcloud-net_launch would fail if they were specified.

Added them in as optional parameters, and extended the tests accordingly.
Merge pull request #52 from mikepea/schema_fix

Add missing schema definitions
Bump vcloud-core dep to 0.11.0 and release 0.6.0

Changes:
  - plaintext passwords are no longer permissible in FOG_RC
    See http://gds-operations.github.io/vcloud-tools/usage/
Merge pull request #54 from gds-operations/bump-core-0.11.0

Bump vcloud-core dep to 0.11.0 and release 0.6.0