Fix use of python-jinja2-26 on EPEL 6
    
    Without this, flask fails to work at all unless python-jinja2
    is installed, and even if it 'works' with that package, that
    package is jinja2 2.2 while Flask 0.9 claims to require >= 2.4,
    so it probably doesn't work properly. With this, Flask properly
    uses the jinja2 2.6 from the jinja2-26 egg.