Update joomla.php

Fixes tracker issue: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=32775&start=0
$ Synching en-GB.lib.joomla.ini after # 32804 commit
correcting
https://github.com/joomla/joomla-cms/commit/092c440ca08888bb89d1ca146ecd459f222c9521#diff-4f99848c581e6fad01897398d2332a63
Merge pull request #2571 from andykirk/patch-1

Update plugins/user/joomla/joomla.php
[#32837] There is an issue in JTableUser class, storing user if user is blocked and no user groups is attached. (Fix #2602)