Commit cursor after creation of wizard instance

Before running InstallUpgrade, the cursor must be committed to avoid
transactional dead lock.

trytond/tests/test_tryton.py

@@ -141,6 +141,7 @@ def install_module(name):
         InstallUpgrade = POOL.get('ir.module.module.install_upgrade',
             type='wizard')
         instance_id, _, _ = InstallUpgrade.create()
+        transaction.cursor.commit()
         InstallUpgrade(instance_id).transition_upgrade()
         InstallUpgrade.delete(instance_id)
         transaction.cursor.commit()