hosts (srv-test-2): Fix nextcloud-sync script

The script was trying to connect via srv-prod-2's IP address but the ssh
config uses 'srv-prod-2' as host identifier. After this change, the
script uses the host identifier from the ssh configuration and also does
no longer pass the user name to connect with, because that's also
configured in ssh config.

systems/x86_64-linux/srv-test-2/configuration.nix

@@ -1,4 +1,4 @@
-{config, ...}: {
+{...}: {
   imports = [
     ../../../modules
     ./nextcloud-sync.nix
@@ -23,13 +23,6 @@
     };
   };
 
-  programs.ssh.extraConfig = ''
-    Host srv-prod-2
-      HostName ${config.my.homelab.srv-prod-2.ip}
-      User nextcloud
-      IdentityFile /etc/ssh/ssh_host_ed25519_key
-      IdentitiesOnly yes
-  '';
   # This value determines the NixOS release from which the default
   # settings for stateful data, like file locations and database versions
   # on your system were taken. It‘s perfectly fine and recommended to leave

systems/x86_64-linux/srv-test-2/nextcloud-sync.nix

@@ -3,8 +3,8 @@
   pkgs,
   ...
 }: let
+  prodHost = "srv-prod-2";
   nextcloud-sync = let
-    prodHost = config.my.homelab.srv-prod-2.ip;
     nextcloudUser = "nextcloud";
     dataDir = "/var/lib/nextcloud/data";
     dbName = "nextcloud";
@@ -15,10 +15,10 @@
       runtimeInputs = [pkgs.rsync config.services.nextcloud.occ];
       text = ''
         nextcloud-occ maintenance:mode --on
-        ssh ${nextcloudUser}@${prodHost} "pg_dump --username=${nextcloudUser} --file=${dbDump} ${dbName}"
-        scp ${nextcloudUser}@${prodHost}:${dbDump} ${dbDump}
-        ssh ${nextcloudUser}@${prodHost} "rm -f ${dbDump}"
-        rsync -avz --delete ${nextcloudUser}@${prodHost}:${dataDir} ${dataDir}
+        ssh ${prodHost} "pg_dump --username=${nextcloudUser} --file=${dbDump} ${dbName}"
+        scp ${prodHost}:${dbDump} ${dbDump}
+        ssh ${prodHost} "rm -f ${dbDump}"
+        rsync -avz --delete ${prodHost}:${dataDir} ${dataDir}
         sudo -u postgres psql --command="DROP DATABASE IF EXISTS ${dbName};"
         sudo -u postgres psql --command="CREATE DATABASE ${dbName} OWNER ${nextcloudUser};"
         sudo -u ${nextcloudUser} psql --dbname=${dbName} --file=${dbDump}
@@ -28,4 +28,12 @@
     };
 in {
   environment.systemPackages = [nextcloud-sync];
+
+  programs.ssh.extraConfig = ''
+    Host ${prodHost}
+      HostName ${config.my.homelab.srv-prod-2.ip}
+      User nextcloud
+      IdentityFile /etc/ssh/ssh_host_ed25519_key
+      IdentitiesOnly yes
+  '';
 }