cmd/geth, eth: move --genesis deprecation warning to cmd/geth

This prevents display of the warning for --dev and --olympic.

cmd/geth/main.go

@@ -359,6 +359,12 @@ JavaScript API. See https://github.com/ethereum/go-ethereum/wiki/Javascipt-Conso
 		go metrics.CollectProcessMetrics(3 * time.Second)
 
 		utils.SetupNetwork(ctx)
+
+		// Deprecation warning.
+		if ctx.GlobalIsSet(utils.GenesisFileFlag.Name) {
+			common.PrintDepricationWarning("--genesis is deprecated. Switch to use 'geth init /path/to/file'")
+		}
+
 		return nil
 	}
 

eth/backend.go

@@ -169,10 +169,6 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 
 	// Load up any custom genesis block if requested
 	if len(config.Genesis) > 0 {
-		// Using println instead of glog to make sure it **always** displays regardless of
-		// verbosity settings.
-		common.PrintDepricationWarning("--genesis is deprecated. Switch to use 'geth init /path/to/file'")
-
 		block, err := core.WriteGenesisBlock(chainDb, strings.NewReader(config.Genesis))
 		if err != nil {
 			return nil, err