Remove warning on EC balancing if no replica placement settings are found. (#6516)

Effectively undoes c9399a68; with ff8bd862, a replica placement type `000`
will no longer break shards re-balancing.

Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>

weed/shell/command_ec_common.go

@@ -194,9 +194,6 @@ func parseReplicaPlacementArg(commandEnv *CommandEnv, replicaStr string) (*super
 		fmt.Printf("using master default replica placement %q for EC volumes\n", rp.String())
 	}
 
-	if !rp.HasReplication() {
-		fmt.Printf("WARNING: replica placement type %q is empty!\n", rp.String())
-	}
 	return rp, nil
 }