testInventoryAPI: commit Zope transaction at the beginning of beforeTearDown().

so that unindexObject SQL query are invoked after another MariaDB transaction for SELECT is committed to avoid deadlock.

product/ERP5/tests/testInventoryAPI.py

@@ -126,6 +126,7 @@ class InventoryAPITestCase(ERP5TypeTestCase):
 
   def beforeTearDown(self):
     """Clear everything for next test."""
+    self.commit()
     for module in [ 'organisation_module',
                     'person_module',
                     'product_module',