Set image_os_type to windows when bootstrap_protocol is winrm and display error_mesage on bootstrap fails.
Updated rspec test to stub ui.info
Implemented review comments to handle Net::SSH::AuthenticationFailed exception inside bootstrapper
Added rspec tests for set_image_os_type
Merge pull request #34 from opscode/adamed-oc-9613-image-os-type

OC-9613: os_image_type should be inferred from bootstrap protocol if not specified to knife cloud