Improve differences between generated mysql service id values

[ryaner]

This uses the entire mac address then reduces the value to the
acceptable range for mysql.

[ryaner]

Some additional background on the reasoning. We've hit multiple collisions with nodes getting the same server-id inside of the same replication chains. It has been getting more common as the number of nodes has increased.

Examples using the old function

mac => "02:00:0a:32:78:cb",
server-id = 2834123
mac => "04:fe:0a:32:7a:4b",
server-id = 2834123

mac => "04:FE:0A:32:79:3B"
server-id = 2834043
mac => "02:00:0A:32:78:7B"
server-id = 2834043

The new method is obviously not perfect but using the entire mac int value and filtering down should reduce collisions.

[ryaner]

I also ran a test using the old vs new method against 1 million random mac addresses.
Old has 7359 collisions. New has 109 collisions.

[daianamezdrea]

Hello @ryaner, thank you for your contribution! This looks good !