Cfy 1272 allow any distribution when installing agents

- removed specific distribution forcing.
- added ability to specify any known agent resource in blueprint under cloudify_config
- supplied download_resource_on_host and get_resource_origin_url functions.
- download_resource_on_host will attempt to use either wget or curl.
dont write 'not accessible', we dont know that caused it really.

just do : 'Failed gettting resource : ex.message..."