Fix C/P fuckup
Get the transaction if we have a name for it

If there is no transaction, we simply go on trying to find it, instead
of cleaning up and possibly forgetting to check whether it is stored
somewhere.
Add missing getref() in ws_deserialize()

Get reference on message here, so we are sure we keep it as long as we
need it.

Pair-programmed-with: Marcel Muller <com2040@gmail.com>
Merge pull request #531 from matthiasbeyer/add-shutdown_transaction_support

Add shutdown transaction support