rhbz#1646916 - handle empty token with complete GSSAPI context
    
    - Add patch to handle empty token with complete GSSAPI context.
      This patch was committed upstream so it should be available in the
      next upstream release.  It should fix rhbz#1646916.
    
    Signed-off-by: Dodji Seketeli <dodji@redhat.com>
    Signed-off-by: Dodji Seketeli <dodji@seketeli.org>