* Release server lock temporarily when BF aborting local SR
transaction during view event processing
* Check transaction state for BF aborts in before_prepare() after
the lock has acquired after fragment removal
* Send rollback fragment only from streaming_rollback()
* Added server_id into transaction in order to be able to stop
streaming applier during high priority BF abort
* Added missing commit fragment applying
* Don't clear fragments for replaying SR transaction
quite useful as there might not be enough information for it
after the statement has been processed. Better to handle retrying
on DBMS side. Also removed after_statement_result enumeration and
return plain int from after_statement().
