This cleans up a lot of junk from crypto_rsa_openssl, and will
save us duplicated code in crypto_rsa_nss (when it exists).
(Actually, it already exists, but I am going to use git rebase so
that this commit precedes the creation of crypto_rsa_nss.)
Fun fact: these files used to be called log.[ch] until we ran into
conflicts with systems having a log.h file. But now that we always
include "lib/log/log.h", we should be fine.
I am calling the crypto library "crypt_ops", since I want
higher-level crypto things to be separated from lower-level ones.
This library will hold only the low-level ones, once we have it
refactored.