Each mount was still loading the manifest and allocator rings and
starting compaction, even if they were coordinating segment reads
and writes with the server.
This moves ring and compaction setup and teardown from on mount and
unmount to as the server starts up and shuts down. Now only the server
has the rings resident and is running compaction.
We had to null some of the super info fields so that we can repeatedly
load and destroy the ring indices over the lifetime of a mount.
We also have to be careful not to call between item transactions and
compaction. We'll restore this functionality with the server in the
future.
Signed-off-by: Zach Brown <zab@versity.com>