2.1-2.2 upgrade script safety checks

[James Fournie]

OS: Ubuntu Lucid
DB: PG 9.1
EG: rel_2_2

Upgrade script contains this:

ALTER TABLE config.upgrade_log DROP COLUMN applied_to;
DROP FUNCTION evergreen.upgrade_list_applied_deprecates(TEXT);
DROP FUNCTION evergreen.upgrade_list_applied_supersedes(TEXT);

This produced errors on our upgrade. Instead I propose:

ALTER TABLE config.upgrade_log DROP COLUMN IF EXISTS applied_to;
DROP FUNCTION IF EXISTS evergreen.upgrade_list_applied_deprecates(TEXT);
DROP FUNCTION IF EXISTS evergreen.upgrade_list_applied_supersedes(TEXT);

[James Fournie (jfournie)]

Pushed a patch to working/user/jamesrf/lp996089

[Lebbeous Fogle-Weekley (lebbeous)]

In master and rel_2_2. Thanks again James!