Fix VPN key generation script

Refactoring of PS broke the VPN key generation script. This MR fixes it again.

Thanks @jcalderone for the ad-hoc pair programming session!

tools/get-vpn-config.nix

@@ -9,11 +9,9 @@
 { pathToGrid }:
 let
   grid = import pathToGrid;
-  vpnConfig = node: node.services.private-storage.monitoring.vpn or null;
-  vpnClientIP = node: (vpnConfig node).client.ip or null;
-  vpnServerIP = node: (vpnConfig node).server.ip or null;
-in
+  vpnIP = node: node.config.grid.monitoringvpnIPv4 or null;  # "or null" since "network" in grid doesn't have a monitoringIPv4
+in rec
 {
- "serverIP" = vpnServerIP grid.monitoring;
- "clientIPs" = builtins.filter (x: x != null) (map vpnClientIP (builtins.attrValues grid));
+ serverIP = vpnIP grid.monitoring;
+ clientIPs = builtins.filter (x: x != serverIP && x != null) (map vpnIP (builtins.attrValues grid));
 }