Bug 18277: [QA Follow-up] Additional polishing

Bug 18277: [QA Follow-up] Additional polishing

Fix POD error in Biblio.pm, as reported by qa tools:
    Apparent command =cut not preceded by blank line

Resolve crash in t/db_dependent/Items/DelItem.t:
  Can't call method "biblio" on an undefined value at C4/Items.pm line 669.

Add find test in tools/batchMod.pl. Increase readability of map statement.

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