vpn: delete removed flag in OpenVPN 2.6

--ncp-disable was deprecated in OpenVPN 2.5 and removed in 2.6. Their rationale is that with the current status of NCP, the option is no longer necessary.

re6st/plib.py

@@ -22,7 +22,7 @@ def openvpn(iface, encrypt, *args, **kw):
     if ovpn_log:
         args += '--log-append', os.path.join(ovpn_log, '%s.log' % iface),
     if not encrypt:
-        args += '--cipher', 'none', '--ncp-disable'
+        args += '--cipher', 'none'
     logging.debug('%r', args)
     return utils.Popen(args, **kw)