RSpec makes define_method public?

Beats me, but I just stumbled upon a passing test that failed IRL because it used the private `Module.define_method`. Seems that after requiring RSpec, it's not private any more.

On Ruby v1.9.3 with RSpec v2.13:
```
>> Object.define_method
NoMethodError: private method `define_method' called for Object:Class
	from (irb):1
	from /usr/local/bin/irb:12:in `<main>'
>> require "rspec"
=> true
>> Object.define_method
ArgumentError: wrong number of arguments (0 for 1)
	from (irb):3:in `define_method'
	from (irb):3
	from /usr/local/bin/irb:12:in `<main>'
```