fixes #6472 / BZ 1113230 - content view filter - fix issue where filter not available

On the content view filter edit screens, it was possible for a
"really fast" user to click links that utilized the filter, before
it had actually been loaded.  Eg. Open a filter and click the 'Add' tab.

This small change will ensure that we do not render the content of the
filter edit, before the filter is actually available.
This is really just covering the case where we are fetching the filter from the server as a result of the user clicking on the filter in the list and perhaps there is some server or network delay in the filter  being returned.   Without this change,  when that delay would occur,the user would see links that required the id and they could click them before the filter was returned resulting in invalid requests to the server.