ValidationChain: fix "re-entering" bug with validation

If we enter the process() function again when the report already has an error,
an InvalidSchemaException is raised even if the schema itself is valid -- but
the data isn't.

Go through an intermediate report instead.

I must test these scenarios :/
1.99.12
Announce 1.99.12

* Brown paper bag release: fix false "invalid schema" reporting.

Francis Galiegue (2):
      ValidationChain: fix "re-entering" bug with validation
      1.99.12