Change links from git://github.com to https://github.com

Change links from git://github.com to https://github.com

I got into troubles to be behind a proxy and my build then fails
because it cannot connect to git://github.com urls

To avoid such problems for others I think it is useful to replace
them for the whole repo. This changes make it work for me again.

Signed-off-by: Matthias Kesler <krombel@krombel.de>