can't set repoToClone to a local directory

[vchudnov-g]

When running node build/cli.js ... --repoToClone=XXX, XXX can currently only be a URL beginning with git@github.com (in this line). However, sometimes we want to test that local changes to XXX will work with our automation before we push the changes to GitHub. In that case, it would be desirable to also allow XXX to be a local filespec and/or a URL beginning with USER@localhost

FWIW, git clone ${USER}@localhost:/PATH/TO/REPO and git clone /PATH/TO/LOCAL/REPO both work just fine.