Fix #305. Ensure that the shard id is set based on the number of current shards + 1. 305 was only occuring if a restart after a Raft log compaction happened
fix bug where writes from the protobuf connection were incorrectly getting logged to the wal and buffered.
Merge pull request #308 from influxdb/fix-305-shard-ids-not-unique-after-restart

Fix 305 shard ids not unique after restart