Adding apache redirect for the cacti url.

As cacti is currently simply being installed via the package
manager, there is no vhosts file. I have added the apache
rewrite rule to apache.conf file that comes with the ubuntu/
debian package.

When accessing the root of the cacti site (cacti.openstack.org)
you will now be redirected to cacti.o.o/cacti/graph_view.php.
I.E:
  RewriteRule ^/$ /cacti/graph_view.php [R,L]

Note, in new deployments the guest user needs to be enabled
otherwise all you'll see is a login screen.

Change-Id: I5242c9daf2ef105b2f685f9f6b2dc4509f9c5dc2
Merge "Adding apache redirect for the cacti url."