Bug 25292: Flushing L1 on every Z3950 server search

Bug 25292: Flushing L1 on every Z3950 server search

This patch flushes the L1 cache on each Z3950 server search.

There is no need to flush it in init_handler (when the connection is
made), the L1 cache is not accessed (this behaviour goes against what I
expected).

This means each search will fetch values from the
L2 cache (ie memcached) and persist the L1 cache (in Perl
memory cache) until the result are returned (or longer?).

Test plan:
% perl misc/z3950_responder.pl --config-dir=/kohadevbox/koha/etc/z3950
% zoomsh
ZOOM>connect localhost:2100
ZOOM>set databaseName biblios
ZOOM>search x
ZOOM>search x

Between the 2 searches you can modify the value of SearchEngine, you
will notice that the number of hits is different

Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit e466c4130406748fdd2d74d5fbee161e4f79cf92)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>