network/simulations: remove log from test printing all hashes

The removed `log.Info()` call produced roughly 1.5k lines per CI run.
To put that into perspective a usual CI run has roughly 10k lines.

Also, I didn't find logging hashes without context very useful. So
I just removed the line. So we have a smaller chance to exceed
Travis' log line limits.

fixes ethersphere/go-ethereum#1189

swarm/network/simulations/discovery/discovery_test.go

@@ -362,9 +362,6 @@ func discoveryPersistenceSimulation(nodes, conns int, adapter adapters.NodeAdapt
 					return fmt.Errorf("error getting node string %s", err)
 				}
 				log.Info(nodeStr)
-				for _, a := range addrs {
-					log.Info(common.Bytes2Hex(a))
-				}
 				if !healthy.ConnectNN || healthy.CountKnowNN == 0 {
 					isHealthy = false
 					break