lnrpc/verrpc: add Versioner RPC server

lnrpc/verrpc/driver.go

@@ -0,0 +1,25 @@
+package verrpc
+
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+)
+
+func init() {
+	subServer := &lnrpc.SubServerDriver{
+		SubServerName: subServerName,
+		New: func(c lnrpc.SubServerConfigDispatcher) (lnrpc.SubServer,
+			lnrpc.MacaroonPerms, error) {
+
+			return &Server{}, macPermissions, nil
+		},
+	}
+
+	// We'll register ourselves as a sub-RPC server within the global lnrpc
+	// package namespace.
+	if err := lnrpc.RegisterSubServer(subServer); err != nil {
+		panic(fmt.Sprintf("failed to register sub server driver '%s': %v",
+			subServerName, err))
+	}
+}