Bug 20482: Correct Terminology codes to Bibliographic ones

Bug 20482: Correct Terminology codes to Bibliographic ones

"RELATIONSHIP TO ISO 639-2
ISO 639-2 (Codes for the representation of names of
languages-- Part 2: alpha-3 code) was based on the MARC
Code List for Languages and published in 1998. In the 22
cases where the ISO 639-2 list has two alternative codes,
the bibliographic code is the same as the MARC code."
(http://www.loc.gov/marc/languages/introduction.pdf)

This leads me to believe that eus, mri, and sqi are
incorrect. The slk code was corrected on an earlier bug.

TEST PLAN
----------
Apply patch
Do a database upgrade
-- Are eus, mri, and sqi fixed?
reset_all
-- Are eus, mri, and sqi never there in the first place?
koha qa test tools only check perl code.

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