Expose server attributes to playbooks.

This makes all of the launch-time attributes (e.g. disk_image_id,
launch_timeout_s, ssh_key_name, etc...) available as facts in case you
need them in a playbook.  They are all in a new fact namespace called
``bang_server_attributes``.
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Fixed aws security group handler
Changed to first delete SG rules and then create and changed from using group names to group ID