Allow more work_mem when upgrading.

[pr0n] / sql / upgrade-v2.50.sql

--
-- Upgrades pre-v2.50 databases to 2.50 format -- not many changes, though.
--
SET work_mem=131072;

ALTER TABLE exif_info RENAME COLUMN tag TO key;
CREATE INDEX exif_info_key ON exif_info ( key );
CLUSTER exif_info_key ON exif_info;