Extend installer to maintain ispconfig.vhost and add ispconfig.vhost options
You can configure the ip address, hostname and port for the apps vhost, but you can not for the ispconfig interface vhost. The port can be changed during installation / update, but other custom changes to the vhost file are overwritten.
The default vhost looks like this (port 8080):
Listen 8080 NameVirtualHost *:8080
If you change to port 443 it looks like this:
Listen 443
NameVirtualHost *:443
Sometimes you need to change it manually to only be served by one ip and hostname like this:
Listen 443
ServerAdmin webmaster@localhost ServerName config.mydomain.com NameVirtualHost *:443
Those settings are not maintained during update, so you have to redo them manually.