Bug 9727: Fix typo in variable name

Bug 9727: Fix typo in variable name

Variable is passed as recordtype not record_type
correct name

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
before applying the patch
$ perl -wc Koha/SearchEngine/Solr/Index.pm
Global symbol "$record_type" requires explicit package name at Koha/SearchEngine/Solr/Index.pm line 43.
Koha/SearchEngine/Solr/Index.pm had compilation errors.

after
Koha/SearchEngine/Solr/Index.pm syntax OK

Signed-off-by: Dobrica Pavlinusic <dpavlin@rot13.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
I can't really test this with solr, but as various people
at the hackfest have confirmed this to be fixing the problem
I feel save to pass QA. All tests and QA script pass too.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>