Address some remaining todos in install script.
Address some remaining todos in install script.

aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,aws/amazon-ecs-init,aws/amazon-ecs-init,aws/amazon-ecs-agent,aws/amazon-ecs-agent,aws/amazon-ecs-init