remove lxc references

plugins/shared/catalog/register_lxc.go

@@ -1,14 +0,0 @@
-//+build linux,lxc
-
-package catalog
-
-import (
-	"github.com/hashicorp/nomad/drivers/lxc"
-)
-
-// This file is where all builtin plugins should be registered in the catalog.
-// Plugins with build restrictions should be placed in the appropriate
-// register_XXX.go file.
-func init() {
-	RegisterDeferredConfig(lxc.PluginID, lxc.PluginConfig, lxc.PluginLoader)
-}