A fork's clone has origin alone. Pushed to the fork's main, the commit
left origin/main...HEAD empty and --changed reported nothing with rc 0.
When no remote names the project, its main is fetched and compared, and
a fetch that fails is an error.
Run from another directory, validate_pr.py read no database, platform or
profile and reported every file as referenced by no platform and outside
bios/. It now moves to the root as verify.py does, reading the files
named from where they were typed.
Under --key the platform restriction was not applied, so dolphin-sys
was downloaded again for RomM, which never reads it. A key whose
platforms exclude the one named is now refused.