it on disconnect.
- Don't rely on own index from the view because the view may come from
another member (IST/SST), instead always determine own index from own ID.
Refs codership/wsrep-lib#13
SR tranasctions are BF aborted or rolled back on primary view
changes according to the following rules:
* Ongoing local SR transactions are BF aborted if the processing
server is not found from the current view.
* All remote SR transactions whose origin server is not included in the
current view are rolled back.
Depending on the DBMS client session allocation strategy the
client id may or may not be available when the client_session
is constructed, therefore there should be a method to assign
an id after construction. Close/cleanup methods were added to
clean up open transactions appropriately.