Bug 19730: (follow-up bug 17196) Use biblio_metadata.timestamp in export_records.pl

Bug 19730: (follow-up bug 17196) Use biblio_metadata.timestamp in export_records.pl

Since bug 17196, biblioitems.timestamp is not always updated after a
change in the MARC record.
Filtering should be based on biblio_metadata.timestamp instead.

REVISED TEST PLAN
-----------------
0. Do not apply patch

1. Find a biblio record, remember the biblionumber for step 3

2. Edit the record, modify a field (e.g. 003, 015$q) that is
   not mapped to a DB column, so biblio_metadata.timestamp will
   be modified but not biblioitems.timestamp

3. In MySQL with the koha database selected:
   > select timestamp from biblio where biblionumber=###;
   > select timestamp from biblio_metadata where biblionumber=###;
   -- you'll need to change the ###'s based on the biblionumber
      you remembered in step 1.
   -- the two timestamps will differ.
   -- Remember the timestamp of biblio_metadata for step 4.

4. Run this command:
   $ sudo koha-shell -c bash kohadev
   $ export DATE="YYYY-MM-DD HH:mm:SS"
   -- use the timestamp remembered in step 3.

5. Run this command:
   $ ./misc/export_records.pl --date="$DATE"
   $ ls -la koha.mrc
   -- the file should be 0 bytes.

6. Run this command:
   $ exit
   $ git bz apply 19730
   $ restart_all
   $ sudo koha-shell -c bash kohadev
   $ export DATE="YYYY-MM-DD HH:mm:SS"
   -- use the timestamp remembered in step 3.

7. Run this command:
   $ ./misc/export_records.pl --date="$DATE"
   $ ls -la koha.mrc
   -- the file should be a lot more than 0 bytes.

8. Run this command:
   $ /home/vagrant/qa-test-tools/koha-qa.pl -v 2 -c 1
   -- this should pass.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>