Patch to send transaction commit/rollback stats to the stats collector unconditionally.

Please find attached the patch to send transaction commit/rollback stats to stats collector unconditionally.

Without this patch, the transactions that do not read from/write to a database table do not get reported to the stats collector until the client disconnects. Hence the transaction counts in pg_stat_database do not increment gradually as one would expect them to. But when such a backend disconnects, the counts jump dramatically, giving the impression that the database processed a lot of transactions (potentially thousands) in an instant.