Cleanup: Fix name not found issue

It's not clear what the origin of this is.
However, the Sequel gem docs clearly document
that if a record doesn't exist, this will return
`nil` rather than raise an exception.

Original error from logs:

```
NameError (uninitialized constant FindResource::NotFound):
app/controllers/concerns/find_resource.rb:23:in `rescue in resource_exists?'
app/controllers/concerns/find_resource.rb:20:in `resource_exists?'
app/controllers/secrets_controller.rb:119:in `error_info'
app/controllers/secrets_controller.rb:23:in `ensure in create'
app/controllers/secrets_controller.rb:30:in `create'
app/controllers/application_controller.rb:83:in `run_with_transaction'
lib/rack/remove_request_parameters.rb:26:in `call'
lib/rack/default_content_type.rb:78:in `call'
```

app/controllers/concerns/find_resource.rb

@@ -18,11 +18,7 @@ def resource
   end
 
   def resource_exists?
-    begin
-      Resource[resource_id] ? true : false
-    rescue NotFound
-      false
-    end
+    Resource[resource_id] ? true : false
   end
 
   def resource_visible?