Don't assume master if 0 master binaries specified

cmd/common.go

@@ -202,9 +202,15 @@ func isMaster() bool {
 	_ = loadConfig(check.MASTER)
 	glog.V(2).Info("Checking if the current node is running master components")
 	masterConf := viper.Sub(string(check.MASTER))
-	if _, err := getBinaries(masterConf); err != nil {
+	components, err := getBinaries(masterConf)
+
+	if err != nil {
 		glog.V(2).Info(err)
 		return false
 	}
+	if len(components) == 0 {
+		glog.V(2).Info("No master binaries specified")
+		return false
+	}
 	return true
 }