There were two issues:
* The original "sealing violation: can't seal package net.corda.nodeapi" issue was due to the isolated CorDapp containing some code in the net.corda.nodeapi namespace. This has been moved to the isolated namespace.
* The test was not correctly creating the second transaction with the dummy command
* Fixed incorrect attachment loading integration test
`AttachmentLoadingTests.test that attachments retrieved over the network are not used for code` was a false-positive - it was incorrect on multiple levels. Fixing it required updating the finance:isolated CorDapp, at which point it was given the new MANIFEST metadata for V4, and moved out of the net.corda.finance namespace to avoid package sealing issues.
The new test exposed a bug in the LedgerTransaction verification logic. This was cleaned up as it was too easy to verify on the wrong instance.
