Remove OBJ_bsearch_()

Remove OBJ_bsearch_()

The only reason this has still been part of the public API was that libssl
used it for cipher lookup. This was fixed by replacing the lookup by proper
bsearch() -- why OpenSSL felt the need to reinvent ANSI C API badly will
forever remain a mystery.

The stack code in libcrypto still uses a version of this. This should
be rewritten. It will be a bit easier once sk_find_ex() is removed.

ok jsing