Bug 11384: (follow-up) update DBIC schema classes

Bug 11384: (follow-up) update DBIC schema classes

This patch updates the DBIC schema class for CollectionTracking
to reflect the new name of its primary key column.

To test:

The CollectionTracking class is not currently used, but
if you *really* want to test this, take a look at the following
branch: http://git.librarypolice.com/?p=koha-galen.git;a=shortlog;h=refs/heads/pg

Then, set up a PostgreSQL database, update koha-conf.xml to point to it,
then run pg/deploy and verify that the collections_tracking table is created
in the Pg database.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>