Revert "Use SHA-1 instead of MD5 for formulae."

This reverts commit cfdb9e63c15e16abae487352b651a56845a5cd3a.
Revert "Revert "Use SHA-1 instead of MD5 for formulae.""

This reverts commit 120996585b20d7da3c2a4fc3627caac475bbf0e6.
Revert "Revert "Revert "Use SHA-1 instead of MD5 for formulae."""

This reverts commit 7b0dd060cdf99eb11f6517e9fdd5c88ceb558685.