update to latest HEAD
    
    - Check /usr for writability before running a transaction.
    - Add repo= arguments to almost all RepoError raises, so we don't print unknown.
    - Add/fix upgrade-minimal typos from man page.
    - Replace vars in include lines in .repo files. BZ 977380.
    - Make --setopt handle spaces properly. BZ 1094373
    - Fix traceback when the history dir is empty. BZ 875610