1.1.3dev: Fix `DatabaseManager` instantiation in `EnvironmentSetup`. Refs #11859.

Passing `self` (the `EnvironmentSetup`) doesn't work here, upgrades would fail with `AssertionError: First argument must be a ComponentManager instance`.

git-svn-id: http://trac.edgewall.org/intertrac/log:/trunk@13462 af82e41b-90c4-0310-8c96-b1721e28e2e2