Default Tx Policy changed to "Required" for session beans

[David Jencks]

I was too lazy to write a descriptor for the jpa integration test in  
geronimo which needs tx to I changed the default Tx Policy for  
session beans to TxRequired in rev 508533.

Dain hinted that this might be required by the ee 5 spec but I  
haven't looked.

thanks
david jencks