Tone down the comment around SSL_set_tlsext_status_ocsp_resp. (#764)

The ownership semantics of SSL_set_tlsext_status_ocsp_resp are not as
complex as the comment suggests. There's no leak or complex lifetime.
It's an ownership transfer of an OPENSSL_malloc'd buffer. The
documentation is lacking, and making the copy internally would have been
tidier (though less efficient if the OCSP response where generated by
i2d_OCSP_RESPONSE), but this sort of thing has precedent in OpenSSL's
1 file changed