Removed aliases for Debian and CentOS as per iproute2

We should not be using aliases anymore. After ifconfig was deprecated and iproute2 took precedence, aliases became a thing of the past. 

As per Debian: "The newer ip utility does not use the same concept of aliases or virtual interfaces." 

Using aliases doesn't break the configuration, but it's probably not the best practice. It's best not to use them.