Fix bug with Trapped Chest support

There is a bug with trapped chests. Non-op players can't lock trapped chest when direct right clicking in the trapped chest with a sign (it always said "no permission to claim container" even if they have "lockette.create.*"). However, it's works when manually placing a sign behind the chest (and manually type "[Private] ...").

I think this little change will fix the problem, I can't test because I can't find some of the required librairies to compile PluginCore.

(sorry for my english which is not my native language)