Drop BIO_n{read,write}{,0}()

Drop BIO_n{read,write}{,0}()

This is one of those strange things that should never have made it into
a security-oriented libraries. From BIO_s_bio.3:

.\" The following non-copying I/O functions are intentionally undocumented
.\" because they seem fragile and unused by anything:

It was used in a single place: the gorgeous ssltest. I'm not smart enough
to follow.  Also:

/* WARNING: The non-copying interface is largely untested as of yet
 * and may contain bugs. */

Oh, really? Into the great bitbucket in the sky you go.

ok jsing