Bug 1594642: Problem where global $sessionpath not set

When I tried closing my site I got DirectoryIterator error

behatnotneeded - the patch 6609 will test this

Change-Id: I35024f8e6a558ee9d009e7c2754a0026e8042b2f
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit 4a4ba694)