This change allows perfectly valid, encoded urls to be visited. (Before they would be double-encoded)
As a consequence of this change, unencoded urls (that need encoding) will not work when visited.
From the capybara list: http://groups.google.com/group/ruby-capybara/browse_thread/thread/9016972307f0427c/ffb27820a0fe4e24?lnk=gst&q=webkit#ffb27820a0fe4e24
visit no longer tries to fix invalid URLs
Merged into master.