Directory:  install/DBUpgrades

Files containing database upgrade code or PHP upgrade code to be run before the
application framework has been intialized can be placed in this directory.  PHP
code that can be run after the application framework has been initialized
should go into install/SiteUpgrades.

All code must be idempotent (no additional effect if run multiple times).

For PHP code, any error messages should be returned by putting them in an array
in $GLOBALS["G_ErrMsgs"].

Upgrade files should be named "DBUpgrade--VERSION.sql" (for SQL code) or
"DBUpgrade--VERSION.php" (for PHP code), where VERSION is the version being
upgraded to.
