HTML entities incorrectly escaped with RUB currency + :no_cents option

This is similar to my other issue, #271, but unlike that one, I'm actually running the latest code.

Steps to reproduce the problem are pretty simple:

```
require 'money'
money = ::Money.new(1999, "RUB")
money.format(:html => true, :no_cents => true)
```

I've even got a spec written for this (see attached). I'll look into why this is happening and see if I can figure it out.