When refreshing the list of tools, we attempted to render a template to

send back to the API call. This was passing a legacy parameter to

RequestContext, which no longer works, causing the refresh spinner to

spin forever and for a traceback to appear in reviewboard.log.
This fortunately did not impede the refresh operation, but it did give

the appearance that refresh had failed.
This change fixes that up, removing the template and just returning a

hard-coded result.

Tested refreshing tools. It successfully refreshed and reloaded the page.