Mirrors speed test fails if mirrors does not use port 80 for http

[Magissia]

If a mirror not using default http port is present in linuxmint.list, mintsource will fail to speedtest it while apt will gladly download packages from the same URL.

Example URL :
http://localcachedomain.local:82/mint

[51CGO]

The file to modify is this one: /usr/share/python-apt/templates/LinuxMint.mirrors
It seems that linuxmint.list is a duplicate and is not used anymore.