Move HTML file "mandriva" to "index.html".

[sjehuda]

Move file "mandriva" to "index.html".

• https://github.com/metalink-dev/website/blob/master/docs/samples/mandriva
• https://github.com/metalink-dev/website/blob/master/docs/samples/mandriva/index.html

Current unwanted behaviour is being prompt to download an HTML file.

http://www.metalinker.org/samples/mandriva