Merge branch 'jk/hash-algo-leak-fixes' into jk/git-hash-cleanups

* jk/hash-algo-leak-fixes: hash: add platform-specific discard functions hash: fix memory leak copying sha256 gcrypt handles http: discard hash in dumb-http http_object_request check_stream_oid(): discard hash on read error patch-id: discard hash when done csum-file: provide a function to release checkpoints csum-file: always finalize or discard hash hash: add discard primitive csum-file: drop discard_hashfile()