Make sure KDF reason codes are conserved in their current state

Make sure KDF reason codes are conserved in their current state

Because KDF errors are deprecated and only conserved for backward
compatibilty, we must make sure that they remain untouched.  A simple
way to signal that is by modifying crypto/err/openssl.ec and replace
the main header file (include/openssl/kdf.h in this case) with 'NONE',
while retaining the error table file (crypto/kdf/kdf_err.c).

util/mkerr.pl is modified to silently ignore anything surrounding a
conserved lib when such a .ec line is found.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10368)