fix: handle flags order validatio better

Closes coop-cloud/organising#214.

cli/server/add.go

@@ -360,6 +360,10 @@ intended as the target server. This is useful when you want to have your entire
 Co-op Cloud config located on the server itself, and not on your local
 developer machine.
 
+Example:
+
+    abra server add --local
+
 Otherwise, you may specify a remote server. The <domain> argument must be a
 publicy accessible domain name which points to your server. You should have SSH
 access to this server, Abra will assume port 22 and will use your current
@@ -394,7 +398,7 @@ You may omit flags to avoid performing this provisioning logic.
 	},
 	ArgsUsage: "<domain> [<user>] [<port>]",
 	Action: func(c *cli.Context) error {
-		if c.Args().Len() > 0 && local {
+		if c.Args().Len() > 0 && local || !internal.ValidateSubCmdFlags(c) {
 			err := errors.New("cannot use '<domain>' and '--local' together")
 			internal.ShowSubcommandHelpAndError(c, err)
 		}