dinghy shouldn't convert to lowercase the URLs

[clopez]

Commit a3d726f broke URL loading when the URL contains uppercase letters.

When I try to open https://people.igalia.com/clopez/webBenchmarks/JetStream/JetStream-1.1/index.html with dinghy it tries to open https://people.igalia.com/clopez/webbenchmarks/jetstream/jetstream-1.1/index.html (everything lowercase), which fails with 404 as expected-

[aperezdc]

Indeed the problem was introduced in a3d726f as you have found out. The string is lowercased to check for the http:// and https:// prefixes always in lowercase and the lowercase string should have been used only for that. I'll make a fix for this.