Bug 5630, follow-up

Bug 5630, follow-up

Fixes chris comment 28, that was a consequence of Marcel comment 27
Recent error
[Thu Sep 01 14:22:45 2011] [error] [client 192.87.126.61] [Thu Sep  1 14:22:45
2011] opac-MARCdetail.pl: DBD::mysql::st execute failed: Unknown column
'limit_desc' in 'field list' at /usr/share/koha/testclone/C4/Auth.pm line 276.
Seems to come from this commit 9a3950f673c28688a2ead6514c3320e34ec0cc4c (5630
CAS Improvements)

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit 1c0702c76e50173289a0ee340a9c5f190515d9c3)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>