This version provides performance improvement for sftp and offers an
option to set TCP_NODELAY. In addition it a new known_hosts API which is
less error prone.

The following bugs have been address by libssh upstream:

BUG 350596
BUG 284867
BUG 296526
BUG 314451

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>