deep_munge

# File actionpack/lib/action_dispatch/http/request.rb, line 253
    def deep_munge(hash)
      keys = hash.keys.find_all { |k| hash[k] == [nil] }
      keys.each { |k| hash[k] = nil }

      hash.each_value do |v|
        case v
        when Array
          v.grep(Hash) { |x| deep_munge(x) }
          v.compact!
        when Hash
          deep_munge(v)
        end
      end

      hash
    end