Function rollback_on_error

This function launches an error

Package: davical\caldav
Copyright: Morphoss Ltd - http://www.morphoss.com/
License: GNU GPL v2 or later version
Author: Andrew McMillan andrew@morphoss.com
Located at caldav-PUT-functions.php

Parameters summary
`boolean`	`$caldav_context`	Whether we are responding via CalDAV or interactively
`integer`	`$user_no`	the user who will receive this ics file
`string`	`$path`	the $path where the PUT failed to store such as /user_foo/home/
`string`	`$message = ''`	An optional error message to return to the client
`integer`	`$error_no = 500`	An optional value for the HTTP error code