Fix existing serial entities that didn't provide .label partners for .accesskey

Fix existing serial entities that didn't provide .label partners for .accesskey

The translate-toolkit project generates a POT file from an input DTD
that requires entities ending in .accesskey to have a corresponding
.label entity; this is a Mozilla convention for localization. Fix up
the serial interface strings that are localized to match this expectation.

Also remove two duplicate entities in lang.dtd that were flagged by
the build/i18n/tests/check_entities.py script (and which cause Launchpad
translation imports to break).

git-svn-id: svn://svn.open-ils.org/ILS/trunk@19277 dcc99617-32d9-48b4-a31d-7c20da2025e4