Switch to more secure SHA256 digest
Switch to more secure SHA256 digest

Change-Id: Ic2e522f125be6bcb0fdef2b0e2993ca98290503f
Closes-Bug: #1488993
Upstream commit: https://github.com/camptocamp/puppet-openssl/commit/f4d27b82a9d220beda51f867ce326c10afa06d43

ddepaoli3/fuel-library-dev,ddepaoli3/fuel-library-dev,xarses/fuel-library,ddepaoli3/fuel-library-dev,xarses/fuel-library,xarses/fuel-library,huntxu/fuel-library,eayunstack/fuel-library,huntxu/fuel-library,eayunstack/fuel-library,huntxu/fuel-library,huntxu/fuel-library,eayunstack/fuel-library,stackforge/fuel-library,stackforge/fuel-library,stackforge/fuel-library,stackforge/fuel-library,eayunstack/fuel-library,ddepaoli3/fuel-library-dev,ddepaoli3/fuel-library-dev,xarses/fuel-library,huntxu/fuel-library,eayunstack/fuel-library