Bug 26448: Don't overwrite commit parameter passed to koha-elasticsearch

Bug 26448: Don't overwrite commit parameter passed to koha-elasticsearch

The "--commit" or "-c" parameter was incorrectly not used if it was
passed to the koha-elasticsearch program.

To test:
1) Before patch notice koha-elasticsearch --rebuild --commit 1 -v <instance>
   only commits every 5000 records
2) Apply patch and notice the above command commits every 1 record

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>