Fix bug 10504: match download's sourceurl mangling in, updxlrator

Fix bug 10504: match download's sourceurl mangling in, updxlrator

Updatexlrator stores its files in a hash of the URL.

The download utility mangles the URL for [+/~], but
the updxlrator only does it for [/]. Thus, download
stores the result as one hash, and updxlrator looks for it
with a different hash. The result is that the file is
re-downloaded every time by both the client, and updxlrator.

This is fixed by making updxlrator mangle the url in the
same way as the downloader. apt-get install g++ would
be a good test for this.

Signed-off-by: Justin Luth  <jluth@mail.com>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>