Bug 12430: Use releance ranking without QueryWeightFields

Bug 12430: Use releance ranking without QueryWeightFields

The system preference "QueryWeightFields" is mutually exclusive with
the system preference "QueryAutoTruncate" and the * truncation
modifier, when not using QueryParser.

If you use truncation, relevance won't work anymore. (N.B. Relevance
doesn't work probably when using QueryParser, but for a very different
reason beyond the current scope of this bug.)

This patch adds relevance ranking when using truncation (or basically
when QueryWeightFields is disabled).

_TEST PLAN_

1) Turn on "QueryWeightFields" and set "QueryAutoTruncate" to auto
2) Turn off "UseQueryParser"
3) Do a keyword search in the OPAC
4) Note that the results are ordered by biblionumber ascending

5) Apply patch

6) Do the same keyword search in the OPAC
7) Note that the results are never ordered differently
(presumably in relevance order :P)

If you're a stickler, throw in some warns so that you can see
what CCL query is being sent to Zebra.

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit f6b5dfa4b718fb74654448b5663cb264b5c376b7)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>