SessionPool logging is using wrong object string to replace #3235
Description
Class: com.google.cloud.spanner.SessionPool
Function: PoolMaintainer.closeIdleSessions(Instant currTime)
logger.log(Level.FINE, "Closing session %s", sess.getName());
Should instead be
logger.log(Level.FINE, "Closing session {0}", sess.getName());
to replace {0} with sess.getName(), otherwise all it's logging is Closing session %s