cleanup --output error message on pgo show cluster and pgo status commands

Author: jmccormick2001

pgo/cmd/cluster.go

@@ -59,6 +59,13 @@ func showCluster(args []string) {
 
 	log.Debugf("showCluster called %v\n", args)
 
+	if OutputFormat != "" {
+		if OutputFormat != "json" {
+			fmt.Println("Error: ", "json is the only supported --output format value")
+			os.Exit(2)
+		}
+	}
+
 	log.Debug("selector is " + Selector)
 	if len(args) == 0 && Selector != "" {
 		args = make([]string, 1)

pgo/cmd/status.go

@@ -51,6 +51,11 @@ func showStatus(args []string) {
 
 	log.Debugf("showStatus called %v\n", args)
 
+	if OutputFormat != "" && OutputFormat != "json" {
+		fmt.Println("Error: json is the only supported --output-format value ")
+		os.Exit(2)
+	}
+
 	response, err := api.ShowStatus(httpclient, &SessionCredentials)
 
 	if err != nil {