Inline EVP_PBE_find() in its last two callers

Inline EVP_PBE_find() in its last two callers

This API was already cleaned up quite a bit, but it is unused in the
ecosystem and the two internal callers can be simplified a lot when
inlining the lookups.

EVP_PBE_CipherInit() can walk the table of "outer" PBEs and reach into
the matching pbe for its cipher_nid, md_nid and keygen().

PKCS5_v2_PBKDF2_keyivgen() uses EVP_PBE_find() as a way to mapping a
PRF (given by the nid of an HMAC with some digest) to the digest's nid.
This can be done by a simple switch. Move MD5 to the top and GOST to
the end in that switch and wrap the latter in OPENSSL_NO_GOST, so it
will go away once we define OPENSSL_NO_GOST.

ok beck