URL Rewriter: redirect to external URL does not work

Reproduction scenario:

Log in to CMS as admin
Go to Documents tab
Open URL rewriter section
Create new advanced rule.
Fill in fields

• in "Rewrite From" field enter some regexp
• in "Rewrite To" field enter "http://www.google.ca/".
  Save and close
  Publish

In the site, enter some URL that matches the regexp.
The site will try to redirect to "http://localhost:8080/http://www.google.ca/".