don't pull libreport-python with libreport
    
    setroubleshoot and python-meh (anaconda) have libreport-python in their
    Requires, so there is no need to have libreport-python in Requires of
    libreport.
    
    The main problem with libreport-python is that it requires 'dnf' in and
    this requirement prevent us from adding libreport and
    abrt-addon-coredump-helper to Atomic hosts.
    
    Signed-off-by: Jakub Filak <jfilak@redhat.com>