fix(GuildChannel#lockPermissions): Properties allow and deny always returning undefined (#2800)

* fix undefined properties

* requested changes

src/structures/GuildChannel.js

@@ -265,8 +265,8 @@ class GuildChannel extends Channel {
   lockPermissions() {
     if (!this.parent) return Promise.reject(new TypeError('Could not find a parent to this guild channel.'));
     const permissionOverwrites = this.parent.permissionOverwrites.map(overwrite => ({
-      deny: overwrite.deny.bitfield,
-      allow: overwrite.allow.bitfield,
+      deny: overwrite.deny,
+      allow: overwrite.allow,
       id: overwrite.id,
       type: overwrite.type,
     }));