Drop conditionals for RHEL
    
    EPEL7 package has different BuildRequires, has couple of additional
    Requires and doesn't have subpackage named python2-pygit2.
    
    This makes it entirely pointless to keep nasty conditionals around
    (which are wrong anyway).
    
    Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>