open up listener on gokrazy

cmd/qrbill-api/api_gokrazy.go

@@ -0,0 +1,9 @@
+// +build gokrazy
+
+package main
+
+func init() {
+	// Open up listener from localhost to all IP addresses, assuming that
+	// running on gokrazy means running as an appliance.
+	defaultListenAddress = ":9933"
+}