Logger should specify connection used in a master/slave situation

Suppose there is a master connection with four slaves specified. Connections are being handled by the Doctrine\DBAL\Connections\MasterSlaveConnection class. Under the current implementation, all queries are logged under the "master" connection, even queries that are routed to the slaves by the Doctrine\DBAL\Connections\MasterSlaveConnection class.

Since slave connections are separate, distinct connections, queries should be logged appropriately under their respective connections.