Revert the fallback hostname revert
    
    Sadly, this does not work.
    
    It seems NM queries resolved for the local IP address and gets "linux"
    and sets that as the transient hostname. Resolved has a "fallback hostname"
    (that will now again be "fedora"), but it also has a fallback fallback hostname
    that is "linux" that it used in reverse dns queries and such. NM gets
    the "linux" name and tells hostnamed to use that as the transient hostname.
    I don't think this is an improvement, since "linux" is a problematic
    as "fedora". So let's revert this for now to avoid pointless churn,
    until we figure out a real solution.