URLs in the personal details description are not linked

Description of the problem:
Urls made in the personal details description do not turn into hyperlinks.

Steps to reproduce:
1. Go to your profile page (e.g. https://launchpad.net/~sitsofe ).
2. Click "Change details" at the top right.
3. Scroll to the Description box. Note the text underneath the Description box says:
"Details about interests and goals. Use plain text, paragraphs are preserved and URLs are linked."
Type http://www.google.com/ into it.
4. Click the Save Changes button.

Expected result:
On the page that appears that http://www.google.com/ should be a clickable link.

Actual result:
http://www.google.com/ is not a clickable link.

Additional information:
If the Description is edited directly on the profile page using the exclamation mark and then clicking the green tick then autolinking will appear to occur. However when the page is refreshed things that looks like URLs will once again not be clickable.

I'm guessing autolinking was disabled for spam reasons and if so the text mentioned in 3 should be changed to say text won't be linked and faux autolinking disabled.

Version information:
r16761