Support for changing the session directory

[Aaron Wells]

As discussed on the forum: https://mahara.org/interaction/forum/topic.php?id=5815

At least two sites have found it helpful to customize the location where Mahara stores its session files. The reason for this is because they're using a relatively slow NFS volume for their dataroot, which works okay for most of the files that Mahara uses, but tends to bog down when it's used for the PHP session save path.

Their workaround is to hack session.php so that it stores the sessions in a directory on their local machine, somewhere outside the dataroot. This bug is for the idea of providing a config option for this, so that it will be unnecessary to hack session.php

[Aaron Wells (u-aaronw)]

https://reviews.mahara.org/2698

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/2698
Committed: http://gitorious.org/mahara/mahara/commit/93cbfb1648c126670501d0a6dad41de92d734399
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit 93cbfb1648c126670501d0a6dad41de92d734399
Author: Aaron Wells <email address hidden>
Date: Tue Nov 12 12:50:51 2013 +1300

Support for custom session save path

Bug 1250256

Change-Id: Iefd489adb4f7d458d1e8b45727fab5509c61398b