Bug 21249: Made the SQL INSERT statement idempotent

Sponsored-BY: Brimbank Library, Australia

Signed-off-by: Amandine Zocca <azocca@ville-montauban.fr>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>

Signed-off-by: David Cook <dcook@prosentient.com.au>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

installer/data/mysql/atomicupdate/bug_21249-Branch_to_limit_advanced_search_results.sql

@@ -1 +1 @@
-INSERT INTO systempreferences (variable, value, options, explanation, type) VALUES ('AdvancedSearchBranchFieldToUse', 'homebranch and holdingbranch', 'homebranch|holdingbranch|homebranch and holdingbranch', 'When a library or group of libraries is selected from the advanced search compare the selected branch value against this branch field(s) selected', 'choice');
+INSERT IGNORE INTO systempreferences (variable, value, options, explanation, type) VALUES ('AdvancedSearchBranchFieldToUse', 'homebranch and holdingbranch', 'homebranch|holdingbranch|homebranch and holdingbranch', 'When a library or group of libraries is selected from the advanced search compare the selected branch value against this branch field(s) selected', 'choice');