Change broken Mcafee link in the readme.

[SoloFausto]

Changed the broken Mcafee link from http://www.mcafee.com/us/downloads/free-tools/stinger.aspx to https://www.mcafee.com/en-us/consumer-corporate/mcafee-labs/free-tools/stinger.html because the last link was leading to the main McAfee website.

[vocatus]

thanks @SoloFausto