The relative service weight output tries to show the relative
chance that any given master in a locaiton will be picked. This
didn't account for all masters having a weight of 0 which would
result in a divide-by-zero error.
Implement the following rules:
1. If all masters have weight == 0 then all are equally
weighted.
2. If any masters have weight == 0 then they have an
extremely small chance of being chosen, percentage is
0.1.
3. Otherwise it's percentage change is based on the sum of
the weights of non-zero masters.
https://pagure.io/freeipa/issue/8135
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
f589a8952c