Statement free or close on leak deferred action should notify errors to database instance

[mrotteveel]

The deferred action for statement free or close operations (including closing of leaked statements) should notify errors to the database instance so it can terminate the connection for fatal errors.

The handling of deferred actions should be overhauled to ensure this is always done, instead of delegating this to the creators of a deferred action.

[mrotteveel]

This will be deferred to Jaybird 6.0.4 or later.

[mrotteveel]

Doing this "the right way" turns out to be harder than I thought. I'm deferring this to Jaybird 7, with maybe a backport to Jaybird 6 after I've figured out what the right way is.

[mrotteveel]

Options I've considered so far:

1. Solving it only for the statement cleanup/free in AbstractFbWireStatement (results in an incomplete solution)
2. Decorating the DeferredAction in AbstractFbWireDatabase.enqueueDeferredAction so that the database exception listener dispatcher is always notified.

Option 2 would cover most bases, but this results in test failures in FbMaintenanceManagerTest.testForcedShutdown due to a NullPointerException instead of an expected SQLException. I'm not yet sure if that means the NPE is the bug, or that the notification itself is the problem.

[mrotteveel]

Back to 6.0.4, as the exception in case of option 2 was indeed a previously hidden bug.