Always ignore createSession parameters

The resource adapter is meant to be used from inside a Java EE
container. In that case, the parameters to createSession are ignored and
the container will manage the transaction.

From EJB 3.1 spc, 13.3.5:

> "Because the container manages the transactional enlistment of JMS
> sessions on behalf of a bean, the parameters of the
> createSession(boolean transacted, int acknowledgeMode) method
> are ignored."
Remove tx synchronization lookup

The RA no longer looks whether there is an active
transaction when the JSM session is created.
Merge pull request #10 from jmesnil/deliveryTransacted

fix transacted delivery behaviour