Update provisioners_controller.rb

Got this error after installing and restarting Foreman:

Error message:
    /usr/share/foreman/vendor/ruby/1.8/gems/foreman_setup-1.0.1/app/controllers/foreman_setup/provisioners_controller.rb:45: syntax error, unexpected ')' )) ^
Merge pull request #10 from Yamakasi/patch-1

Update provisioners_controller.rb