Bug 15485: (QA followup) Fix behaviour and default values

Bug 15485: (QA followup) Fix behaviour and default values

Jonathan noticed the current behaviour is that the lists rendering
falls back to the XSLTResults, and if not defined (i.e. != 'default' and
!= some_path) it falls back to a legacy display (non-XSLT).

The patchset changed this behaviour because 'default' is not a valid value
for the lists. So it should fallback to the current behaivour (i.e. Results
XSLT configuration) if not defined. This patch fixes this by adding
 || C4::Context->preference('XSLTResultsDisplay')
(and the OPAC counterpart).

It also fixes minor glitches on the update message (oops) and bad default value
in sysprefs.sql  for 'XSLTListsDisplay'.

Thanks Jonathan!

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>