Improvements to repo checkout
Improvements to repo checkout

exists -> exist to prevent warning in rspec
use git:// vs. https:// for checkout to prevent credentials prompt
improve the error message on failure

pkang/foodcritic,Foodcritic/foodcritic,offslinker/foodcritic,acrmp/foodcritic,nathenharvey/foodcritic,chazzly/foodcritic,tas50/foodcritic,akihiro17/foodcritic,clintoncwolfe/foodcritic