Bug 8546 - Error in description of OPAC Advanced Search Publication date range search

Bug 8546 - Error in description of OPAC Advanced Search Publication date range search

The publication date range search description in the OPAC suggests
that a search like "-1987" or "2008-" is not inclusive when it
actually is. This patch corrects the description.

Signed-off-by: Melia Meggs <melia@test.bywatersolutions.com>
Passed-QA-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>