add context: fix build (#46)

Summary:
The build public build broke after D53320510.

Pull Request resolved: #46

Reviewed By: xaionaro

Differential Revision: D53407901

fbshipit-source-id: c5268007e5ebda76380e35324e96f3c2156c5e68

main.go

@@ -8,6 +8,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"net/http"
@@ -30,6 +31,9 @@ func main() {
 	flag.Parse()
 	flag.Lookup("logtostderr").Value.Set("true")
 
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	if *configPath == "" {
 		glog.Fatal("Config file is necessary")
 	}
@@ -75,5 +79,5 @@ func main() {
 	}()
 
 	glog.Infof("Starting dhcplb in v%d mode", *version)
-	glog.Fatal(server.ListenAndServe())
+	glog.Fatal(server.ListenAndServe(ctx))
 }