Bug 10134 - set XSLT usage ON as default, for new Koha installs

Bug 10134 - set XSLT usage ON as default, for new Koha installs

Currently, new installs are created with XSLT display set to "off",
but XSLT seems to be the preferred way to display records, so
having the default be "on" instead seems to make sense. This patch
will of course only affect new installs.

To test:
- Apply the patch
- Run through the webinstaller on an empty database
- Log in to the staff client and search for "xslt" in system
  preferences
- Verify that XSLTDetailsDisplay, XSLTResultsDisplay,
  OPACXSLTDetailsDisplay and OPACXSLTResultsDisplay are all set to
  "default"

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Passes test plan correctly.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Changes syspref.sql for new installations to use XSLT views
by default. No changes to existing installations, no
string changes.
Passes all tests.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>