Bug 24788: Remove autoloaded column accessors in Koha::Object->store

Bug 24788: Remove autoloaded column accessors in Koha::Object->store

Columns are accessed as methods, relying on AUTOLOAD, in
Koha::Object->store. This could be a source of strange bugs
if a column name clashes with an existing method name.

To test:

1) Apply patches for Bug 14957
2) Follow the testing instructions, when saving a new marc rule and
error is thrown.
3) Apply patch
4) Try saving a new rule once again, this should now work

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>