PR Request on Github from Joomla Code Patch

http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=30235

Angelika Reisiger was supplying a patch on joomlacode which has been patched here too now.
Merge pull request #3881 from dam-man/patch-1

[#30235] JSession::get() returns NULL under normal session operations