Switched to tarball. Should be faster.

Codeload is used as the regular tarball is on the rtorrent github page
with rtorrent's versioning.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Used a patch that was merged upstream.

Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>