* Remove logging init from storage program: saw a crash in a test
indicating the logger being init'ed twice.
* Add entry_height mining proof to indicate which segment the result is
for
* Add an interface to get storage miner pubkeys for a given entry_height
* Add an interface to get the current storage mining entry_height
* Set the tvu socket to 0.0.0.0:0 in replicator to stop getting entries
after the desired ledger segment is downloaded.
* Use signature of PoH height to determine which block to download for
replicator.