Provide a way to run a cleanup script after a deployment error

CodeDeploy is missing a mechanism for doing cleanup after a deployment error. This could be implemented as another lifecycle event that is triggered only when a deployment fails for some reason. This reason could be e.g. a non-zero exit status of a hook script, a timeout or a user-triggered cancellation of the deployment.

The idea of this originates from [a more specific issue regarding ASG lifecycle scripts](https://github.com/awslabs/aws-codedeploy-samples/issues/42). In that case, an auto-scaling group is left in an unclean state after an error during a deployment.

One remotely similar mechanism for error handling is the `rescue` block in Ansible:
http://docs.ansible.com/ansible/playbooks_blocks.html

Empieza leyendo el comportamiento de los eventos del ciclo de vida de CodeDeploy descrito aquí y el issue 42 enlazado sobre los scripts del ciclo de vida de ASG. Compara los casos de fallo propuestos —errores de hooks, timeouts y cancelaciones— con la referencia de Ansible's rescue-block. Se consideraría terminado cuando exista un diseño acordado para un evento de cleanup y su comportamiento en esos casos de fallo.

Escrito por el modelo de indexación a partir del texto del issue.