node: ensure datadir can be co-inhabited by different instances

This change ensures that nodes started with different Name but same
DataDir values don't use the same nodekey and IPC socket.

cmd/geth/consolecmd.go

@@ -107,7 +107,7 @@ func remoteConsole(ctx *cli.Context) error {
 		utils.Fatalf("Unable to attach to remote geth: %v", err)
 	}
 	config := console.Config{
-		DataDir: utils.MustMakeDataDir(ctx),
+		DataDir: utils.MakeDataDir(ctx),
 		DocRoot: ctx.GlobalString(utils.JSpathFlag.Name),
 		Client:  client,
 		Preload: utils.MakeConsolePreloads(ctx),
@@ -135,7 +135,7 @@ func remoteConsole(ctx *cli.Context) error {
 // for "geth attach" and "geth monitor" with no argument.
 func dialRPC(endpoint string) (*rpc.Client, error) {
 	if endpoint == "" {
-		endpoint = node.DefaultIPCEndpoint()
+		endpoint = node.DefaultIPCEndpoint(clientIdentifier)
 	} else if strings.HasPrefix(endpoint, "rpc:") || strings.HasPrefix(endpoint, "ipc:") {
 		// Backwards compatibility with geth < 1.5 which required
 		// these prefixes.