BSON::OrderedHash can be corrupted

steps to reproduce:
execute the following lines:

a = BSON::OrderedHash.new
a[:b] = :c
a.replace(:c => :d)

results

a is corrupted. For instance it inspects as:

instead of:
{:c => :d}

the method 'replace' on Hash is not overridden !!!!!!!

implementation suggestion:

def replace(other_hash)
@ordered_keys.replace(other_hash.keys)
super
end