GenerateSchema mode leaves autoCreate/validate turned on

[andyjefferson]

When we start up a PMF/EMF with create/drop scripts for creating the database schema we currently turn the auto-create/validate flags to true, presumably to allow any scripts to be invoked. See https://github.com/datanucleus/datanucleus-core/blob/master/src/main/java/org/datanucleus/PersistenceNucleusContextImpl.java#L415

This means that those settings are ON thereafter, so any FKs that we did not create during schema generation from script will be generated automatically. Which we don't want.

Do we really even need these properties enabling in the first place just to invoke script commands?

[andyjefferson]

Turns out those properties are only needed to be added when GENERATING SCRIPTS, and not when executing scripts to create the database

[andyjefferson]

Actually jpa/jta tests show a problem if we do this, so reverted the change. Find a better way to fix the issue