dist-git: don't setgid(apache) while importing ("uploading")
    
    I'm totally familiar with the previous practice (I was fixing related
    permissions problems while deploying Copr instances before) but it seems
    entirely redundant.
    
    First, the directories have 'setgid' bit anyway, so new files are
    owned by apache group anyway and thus swtiching EGID shouldn't be
    needed?  And second, Apache (cgit&others) processes should be OK with
    just plain read-only access to those files (while "others" have the r-x
    permissions there).
    
    This fix is needed to allow running DistGit importer in OpenShift, where
    we have an artificial UID and root (0) GID, and we can not simply switch
    from one GID to another.
    
    Merges: #2195