Reserved IP allocations do not always persist

[jtmusson]

I have not yet been able to identify steps to reproduce, but it has occurred more than once on different scopes.

A device with an identifier allocated to a reserved IP can be given a different IP from with the scope's range to allocate. When this happens the lease previously marked as "Reserved" disappears from the list.

Workaround is to edit the lease to the desired IP, mark as Reserved and then renew lease on the device, then it is issued the reserved IP.

Working on latest release, docker via docker-compose. 3 nodes.

Happy to help with steps to troubleshoot.

[tigattack]

To add some more context to this and #871 (the two seem to go hand in hand), I only see it happen after making major changes to Gravity.

For example, I saw it upon initial deployment, and it began reoccurring after I added another two nodes (for a total of 3) to the cluster yesterday. In both cases, the frequency of both issues reduces over time, typically down to almost zero after a few days and rarely occurring thereafter.