Rollback of nested transaction is not handled correctly

_From [st.classen@gmx.ch](https://code.google.com/u/106496239342698547677/) on January 30, 2012 18:42:43_

When an transaction hits an exception and should trigger a rollback it might not happen if the transaction is a nested transaction.
It will not happen if either the following is the case.
 1. The  most transaction does not rollback on this type of exception
 2. If some exception handler between the inner and the outer most transaction swallows the exception.

Attached is a patch containing 3 commits.
 1. commit: added unit test to reproduce the issue
 2 . commit: fix to the issue
 3 . commit: fixed an old TODO in the code

**Attachment:** [gist](https://gist.github.com/d3a20448c0570a767151)
   _[nestedTransaction.patch](https://gist.githubusercontent.com/gissuebot/d3a20448c0570a767151/raw/1f76161e1e8480ddca1e25d47027340f76af4972/nestedTransaction.patch)_

_Original issue: http://code.google.com/p/google-guice/issues/detail?id=682_