Customer email:

"I was sent to an errror page on clicking on 'Systems' on my "Your RHN" home
page. Clicking on the 'Systems' button in the banner at the top of the page
works but the 'Systems' link in the text of the page does not."

Explanation:

If a customer only has update entitlements, they can't see system search since
it's a management-only feature. So, we should acl that link such that only
management-entitled customers can see it.

(as an aside it'd be nice to open up system search to all customers since we
don't really enforce it well anyway. if you bought 1 single mgmt entitlement and
it expired long ago apparently you can still system search. it's pretty basic
functionality.)