adjust frequency of geom rebuild notifications.
When a geom rebuild is occurring, the gmirror_status_check script by default notices that the device status has changed every time the rebuild hits a new percentage.
This results in a user getting 100 separate notifications (emails) every time a new percentage ticks.
I have submitted a PR that changes this behavior, so a user only gets notified at 0%, 25%, 50%, 75% and 100%. This should not effect any other notification behavior.