*Description of problem: "can not set password with opaque" error on settings page after creating Http proxy with invalid url.

Steps to Reproduce:

1. Go to Infrastructure > Http Proxies
2. Create a http proxy with invalid url. (like http:invalid.com)
3. Go to Administer > Settings

Actual results:
Oops, we're sorry but something went wrong: can not set password with opaque

Expected results:
Settings page should be accessible