Merge pull request #5402 from hashicorp/lxc_cleanup

delete unneeded plugin file

plugin/builder-lxc/main.go

@@ -1,15 +0,0 @@
-package main
-
-import (
-	"github.com/hashicorp/packer/builder/lxc"
-	"github.com/hashicorp/packer/packer/plugin"
-)
-
-func main() {
-	server, err := plugin.Server()
-	if err != nil {
-		panic(err)
-	}
-	server.RegisterBuilder(new(lxc.Builder))
-	server.Serve()
-}