Update smtp settings
Update smtp settings

It is bad, that we have it hardcoded. For this reason we now have the
following issue:
https://github.com/Mehonoshin/smartvpn-billing/issues/94

smartvpnbiz/smartvpn-billing,smartvpnbiz/smartvpn-billing,smartvpnbiz/smartvpn-billing,smartvpnbiz/smartvpn-billing,smartvpnbiz/smartvpn-billing