Comment javascript broken since 4.4

[ssnepenthe]

Hey Mark - it looks like the comment 'logged in as' link text changed in 34535 and is no longer empty.

Because of this, loggedInMessage.find 'a[href=""]:empty' no longer works to select this element.

The next line will need an update as well because the link text should now read 'Logged in as {username}'.

[grappler]

This PR should fix it https://github.com/markjaquith/cache-buddy/pull/12