Executive summary

This PR updates the FOF version included in Joomla! to FOF 2.4.1. This is required to fix a major bug in com_postinstall (Post Installation Messages) which results in the Joomla! Control Panel displaying a SQL error complaining about invalid SQL. This is a show stopper bug affecting a small but significant number of people (they've started asking me about it directly, that's how I found out).

Technical description

When updating some sites to Joomla! 3.3.6 you get a strange situation where the filter_order user state is set to an empty string and the FOF table cache is broken. This leads to PostinstallModelMessages to generate an invalid SQL query ending in ORDER BY `` ASC (note the empty column name). This happens because FOFModel lacks a safeguard against ordering by an empty column. Moreover, it is possible to set the filter_order_Dir user state to something other than ASC/DESC, also resulting in invalid SQL because there is no check on the validity of its value.

Test instructions

Before installing this PR go to Components, Post-Installation Messages. Edit the URL at the top of the page and append &filter_order_Dir=foobar. You get an immediate error message.

Install this PR. Repeat the steps above. There is no SQL error and the component works correctly.

Also check that after installing the PR you can hide post-installation messages, show them again and that the Two Factor Authentication still works.