OpenSSL: Correct the return value of BIO_get_ktls_*().

BIO_get_ktls_send() and BIO_get_ktls_recv() are documented as
returning either 0 or 1. However, they were actually returning the
internal value of the associated BIO flag for the true case instead of

Also trim redundant ternary operators.

Reviewed by: jkim
Obtained from: OpenSSL (f16e52b67c9261bdc7e1284a50502a802921ac6d)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31438