SpringTransactionManager calls lifecycle methods on tx instead of tx manager

to let the Kernel API be apart of the commit/rollback, something that a call directly
to tx manager commit/rollback would leave out.

Committing on behalf of Michael Hunger, @jexp
Merge pull request #1161 from tinwelint/2.0-spring-txmgr-kernelapi-interop

SpringTransactionManager calls lifecycle methods on tx instead of tx mgr