Suppress "Refresh failed" alert message for debug mode toggle

Brion pointed out there's no urgent reason to show the "Refresh failed" message at all when toggling debug mode, whereas on the My Uploads page it's actually informative as it tells you one reason why you may not be seeing images.

So makes sense to just suppress the message if it's triggered by the toggle.
Merge pull request #60 from montehurd/doubleRefresh

Suppress "Refresh failed" alert message for debug mode toggle