cmd/geth: reintroduce wallet import subcommand

cmd/geth/accountcmd.go

@@ -32,7 +32,21 @@ import (
 var (
 	walletCommand = cli.Command{
 		Name:      "wallet",
-		Usage:    "Import Ethereum presale wallets",
+		Usage:     "Manage Ethereum presale wallets",
+		ArgsUsage: "",
+		Category:  "ACCOUNT COMMANDS",
+		Description: `
+    geth wallet import /path/to/my/presale.wallet
+
+will prompt for your password and imports your ether presale account.
+It can be used non-interactively with the --password option taking a
+passwordfile as argument containing the wallet password in plaintext.`,
+		Subcommands: []cli.Command{
+			{
+
+				Name:      "import",
+				Usage:     "Import Ethereum presale wallet",
+				ArgsUsage: "<keyFile>",
 				Action:    utils.MigrateFlags(importWallet),
 				Category:  "ACCOUNT COMMANDS",
 				Flags: []cli.Flag{
@@ -46,10 +60,11 @@ var (
 
 will prompt for your password and imports your ether presale account.
 It can be used non-interactively with the --password option taking a
-		passwordfile as argument containing the wallet password in plaintext.
-
-		`,
+passwordfile as argument containing the wallet password in plaintext.`,
+			},
+		},
 	}
+
 	accountCommand = cli.Command{
 		Name:     "account",
 		Usage:    "Manage accounts",