Revert "adding retries option to hdf backend"
Revert "adding retries option to hdf backend"

This reverts commit 8642e1b2ca79016525aada6947fab5c4f3badb36.

willvousden/emcee,dfm/emcee,johnbachman/emcee,farr/emcee,joezuntz/emcee,willvousden/emcee,johnbachman/emcee,dfm/emcee