Does not handle start_failed instance status

[brad811]

They have the full list of possible statuses here:
http://docs.aws.amazon.com/cli/latest/reference/opsworks/describe-instances.html

• booting
• connection_lost
• online
• pending
• rebooting
• requested
• running_setup
• setup_failed
• shutting_down
• start_failed
• stop_failed
• stopped
• stopping
• terminated
• terminating