openvpn: Enable IPv6 for server and client outside the tunnel

This enables clients to connect to servers on IPv6 networks. After the
connection, the tunnel works just like before.

- Make sure that after upgrading the server configuration, if the server is
  running (which means it was enabled), restart the server to reflect the new
  configuration.

- Don't increment the app version number as it has already been incremented in
  this release cycle.

Tests:

- Check that the listen address before the change is 0.0.0.0:1194 and after
  upgrade (temporarily increment app version number again) the listen address
  automatically changes to *:1194.

- Download the new client profile and use it connect to the server on IPv4
  network and observe that there is error during connection.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/openvpn

@@ -50,6 +50,7 @@ ATTR_FILE = os.path.join(KEYS_DIRECTORY, 'pki', 'index.txt.attr')
 SERVER_CONFIGURATION = '''
 port 1194
 proto udp
+proto udp6
 dev tun
 client-to-client
 ca /etc/openvpn/freedombox-keys/pki/ca.crt
@@ -67,6 +68,7 @@ CLIENT_CONFIGURATION = '''
 client
 remote {remote} 1194
 proto udp
+proto udp6
 dev tun
 nobind
 remote-cert-tls server
@@ -209,6 +211,8 @@ def subcommand_upgrade(_):
         action_utils.service_disable(OLD_SERVICE_NAME)
         action_utils.service_enable(SERVICE_NAME)
 
+    action_utils.service_try_restart(SERVICE_NAME)
+
 
 def _write_server_config():
     """Write server configuration."""