[FIX] base: allow uninstall of modules to upgrade

Commit 8c1bb22e forgot to take into
account migrations, during a migration it is possible that some modules
need to be uninstalled because the target version may have removed /
moved them and since during a migration all modules are set `to
upgrade`, the previous condition made this impossible for migration
scripts that use the ORM for module uninstalls (not Odoo's case, mind
you)

With this commit it is again possible to uninstall modules from a
migration script during a migration.

closes odoo/odoo#50302

X-original-commit: a7c90a6d
Signed-off-by: Raphael Collet (rco) <rco@openerp.com>
Signed-off-by: Adrian Torres (adt) <adt@odoo.com>