Fixed working count and total count being inverted when generating percentage

I noticed this while updating this gem for Rubinius. 

To reproduce:

* rvm use 1.9.2 (if using RVM)
* gem install rubygems-isit19
* gem install johnson

You should see: 

johnson 1.2.0 might work, 100% say 2.0.0.pre3 works on 1.9
Update http://isitruby19.com/johnson with your experiences!

When you go to isitruby19.com/johnson, you'll notice that no one has said johnson 2.0.0.pre3 will work on 1.9. If you try gem install johnson -v 1.1.0 (1 person said yes, 1 person said no), you'll still get 100%. 

After the attached change, you should see:

johnson 1.2.0 might work,  0% say 2.0.0.pre3 works on 1.9
Update http://isitruby19.com/johnson with your experiences!

If you gem install johnson -v 1.1.0, you'll see 50% as expected.