Require moniker instead of generating a random one

PENDING.md

@@ -34,7 +34,7 @@ IMPROVEMENTS
   * [\#2749](https://github.com/cosmos/cosmos-sdk/pull/2749) Add --chain-id flag to gaiad testnet
 
 * Gaia
-  * Generate a random moniker on `gaiad init` if one was not provided.
+  * Require moniker to be provided on `gaiad init`.
 
 * SDK
  - [x/mock/simulation] [\#2720] major cleanup, introduction of helper objects, reorganization

cmd/gaia/init/init.go

@@ -64,7 +64,7 @@ func InitCmd(ctx *server.Context, cdc *codec.Codec, appInit server.AppInit) *cob
 
 			moniker := viper.GetString(flagMoniker)
 			if moniker == "" {
-				moniker = fmt.Sprintf("gaianode-%v", common.RandStr(6))
+				return fmt.Errorf("required flag \"%s\" has not been set", flagMoniker)
 			}
 
 			config.Moniker = moniker