Let “ccache --hash-file” perform raw hashing again

Let “ccache --hash-file” perform raw hashing again

Unintended or not, #577 (213d9883) changed the behavior of “ccache
--hash-file” to use hash_binary_file, which essentially performs
hash(hash(path)) if the i-node cache is enabled, otherwise hash(path).
This means that “ccache --hash-file” behaves differently depending on if
i-node cache is enabled and also that it’s no longer usable for
benchmarking purposes.

Fix this by simply using “hash_file” again.