Bug 8665 follow-up: add missing line to XSLT

Bug 8665 follow-up: add missing line to XSLT

The DOM transformer was missing a line from a previous development,
resulting in the MARC21 authorities DOM indexing stylesheet being
regenerated with a missing line. This patch readds the missing line
to the transformer, and provides the corrected authority-zebra-indexdefs.

Signed-off-by: Elliott Davis <elliott@bywatersolutions.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Conflicts:
	etc/zebradb/xsl/koha-indexdefs-to-zebra.xsl

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>