5936: Remove some obsolete db columns from aqbooksellers and aqbudgets if needed

5936: Remove some obsolete db columns from aqbooksellers and aqbudgets if needed

Removes obsolete columns from aqbooksellers and aqbudgets if needed.
aqbooksellers: deliverydays followupdays followupscancel invoicedisc nocalc
specialty
aqbudgets: budget_description

These columns should not exist in a fresh install from kohastructure.sql, but
originate from older 3.0 versions.
One line in acqui/updatesupplier.pl referring to one of these columns is
removed too.

This patch therefore does not change functionality, but only keeps your db in
shape.

Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Rebased April 6.
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>