Update docs for SSH host keys replication step

doc/administration/geo/replication/configuration.md

@@ -127,7 +127,11 @@ keys must be manually replicated to the secondary node.
 1. Restart sshd:
 
     ```bash
-    service ssh restart
+    # Debian or Ubuntu installations
+    sudo service ssh reload
+
+    # CentOS installations
+    sudo service sshd reload
     ```
 
 ### Step 3. Add the secondary GitLab node