int libssh2_knownhost_get(LIBSSH2_KNOWNHOSTS *hosts,
struct libssh2_knownhost **store,
struct libssh2_knownhost *prev):
store should point to a pointer that gets filled in to point to the known host data.
prev is a pointer to a previous 'struct libssh2_knownhost' as returned by a previous invoke of this function, or NULL to get the first entry in the internal collection.
Returns 1 if it reached the end of hosts.
Returns negative values for error