BUILD: Avoid symlinks with python modules
    
    We need to use different names for python{2,3} modules if we want to build
    them in the same time with automake (prefix _py2 and _py3). But resulting name
    need to correspond with name of module because it is used in C import function.
    We used symbolic links for that purpose but it breaks debian python tools
    which rename the real modules making symbolic links to point nowhere
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/2814
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    (cherry picked from commit bf0002fa68e9c06f0569cf75b1b8ef85bb1c2697)