Retry a failed command after some time. Retry the command specified if running it the first time fails. The time delay, and the number of retrys, to be configurable.

Example usage:

$ retry -d 10 -t 2 wajig daily-upgrade

That is, run wajig daily-upgrade, if it fails wait ten seconds and try it again. Do that a maximum of two times.

Done: retry.py