Remove unused check_schema_version function from index_postgres.sql

We are not using this function since 57174ca4fa5414e69678f7b9b0d27fde692e393.

Change-Id: I5faccf18760cd74774b6ad336192bc1beaf3dca8
Signed-off-by: Sasa Zivkov <sasa.zivkov@sap.com>
diff --git a/gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_postgres.sql b/gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_postgres.sql
index 2c91db4..675c5bc 100644
--- a/gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_postgres.sql
+++ b/gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_postgres.sql
@@ -47,30 +47,6 @@
 
 DROP FUNCTION make_plpgsql();
 
--- Define our schema upgrade support function.
---
-
-delimiter //
-
-CREATE OR REPLACE FUNCTION
-check_schema_version (exp INT)
-RETURNS VARCHAR(255)
-AS $$
-DECLARE
-  l_act INT;
-BEGIN
-  SELECT version_nbr INTO l_act
-  FROM schema_version;
-
-  IF l_act <> exp
-  THEN
-    RAISE EXCEPTION 'expected schema %, found %', exp, l_act;
-  END IF;
-  RETURN 'OK';
-END;
-$$ LANGUAGE plpgsql;
-//
-
 delimiter ;
 
 -- Indexes to support @Query