change macro format for source repos
changed from gitN, commitN to git_$repo, commit_$repo to better track what
macro is used by a repo. Also helps to make things uniform between rhel and
fedora given that sub-repos enter and leave docker all the time.
also, d-s-s is now renamed to container-storage-setup, so downloaded
tarball uses the new name.
Signed-off-by: Lokesh Mandvekar <lsm5@fedoraproject.org>