url: fix bug in passwordmgr related to auth configuration
Usernames given as part of the URL would be ignored.
This bug was introduced in 89c80c3dc5842d609e9ba13f08fd2cf7f127c25a
http://example.com/no/anchor, revs: None, checkout: None
http://example.com/an/anchor, revs: ['foo'], checkout: 'foo'
http://example.com/no/anchor/revs, revs: ['foo'], checkout: 'foo'
http://example.com/an/anchor/revs, revs: ['foo', 'bar'], checkout: 'foo'
http://example.com/an/anchor/rev-None, revs: ['foo'], checkout: 'foo'