erp5_catalog: [WORKAROUND] Explicitly call reset for component_tool in test.

Problem:
This is a workaround for components being unable to get registered during
the tests.

Explanation:
After adding document component object, _p_oid is generated at the
last step of commit hook. This leads to problem that _registry_dict for
dynamic_class 'erp5.component.document' isn't getting updated with
the _p_oid of the component created.
This leads to failing of test because to validate object with same
reference, the checkConsistency function checks in the _registry_dict
for reference and _p_oid.

Solution:
Explicilty calling transaction.savepoint here generates the oid before validation, hence
make it available for the registry_dict in time.

But, this clearly is a workaround which is clearly not solving the real
problem of why the _p_oid isn't being generated at the right step.

product/ERP5Type/tests/testDynamicClassGeneration.py

@@ -1967,6 +1967,7 @@ def bar(*args, **kwargs):
     reference = 'ValidateComponentWithSameReferenceVersionAlreadyValidated'
 
     component = self._newComponent(reference, 'def foo():\n  print "ok"')
+    transaction.savepoint(optimistic=True)
     component.validate()
     self.tic()