Crave: Do not modify repo if it is running on Devspace CLI

[sounddrill31]

Crave Devspace CLI already provides a system for cloning ROMs, and the repo tool we use is a shim which tells users not to do this.

People starting off using convenience tools like this sometimes don't read the community written documentation properly and tend to unknowingly circumvent the rules which we want to avoid

Please don't hesitate to let me know if there's a better way or if I have made any mistakes.