Commit Briefs
remove now unused sha1 handling from inflate and deflate
both were changed to use the new got_hash APIs.
add some helper functions to compute hashes
This adds a set of functions to abstract over SHA1Init, SHA1Update, SHA1Final, their respective SHA256 variants and how to compare digests. Replace all the SHA1*() usage with the new APIs. It's a preparatory step for sha256 handling. ok stsp@