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
#!/bin/sh
hg init
touch a
hg add a
hg ci -m "a" -d "1000000 0"
echo 123 > b
hg add b
hg diff --nodates
hg diff --nodates -r tip
echo foo > a
hg diff --nodates
hg diff -r ""
hg diff -r tip -r ""
true