keyfiles: Fixed possible problem with known_hosts path.

libssh/keyfiles.c

@@ -1725,7 +1725,7 @@ int ssh_write_knownhost(ssh_session session) {
   }
 
   if (session->knownhosts == NULL) {
-    if (ssh_options_set(session, SSH_OPTIONS_KNOWNHOSTS, NULL) < 0) {
+    if (ssh_options_apply(session) < 0) {
       ssh_set_error(session, SSH_FATAL, "Can't find a known_hosts file");
       return -1;
     }