Bug 18897: Use Module::Load::Conditional::can_load

Bug 18897: Use Module::Load::Conditional::can_load

Rather than rely on eval(), Jonathan Druart recommended in
comment #6 to use Use Module::Load::Conditional::can_load.
This addresses that concern.

TEST PLAN
---------
$ git fetch
$ git checkout -b bug_18897 origin/master
$ git bz apply 18897
$ sudo apt-get remove libcatmandu-store-elasticsearch-perl
...
$ prove t/db_dependent/Koha_Elasticsearch_Indexer.t
-- Note that the message says the correct library is missing.
$ sudo apt-get install libcatmandu-store-elasticsearch-perl
-- Note it runs as expected.
run the koha qa test tools

Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>