Uses a structure like:
/root/
/db1/rp1/1
/2
/db2/rp2/3
If a write is assigned to a shard on the local node but the shard
has not been created, create it when the write returns an error
and retry the write.
This allows the new write path to be hooked up if you start the
server with `INFLUXDB_ALPHA1=1`. When set, writes will go though
the coordinator and be stubbed out to write to a single local data
node with one shards. The write will be logged and written to
disk .
The env var is used so that the current write path is not completely
broken which would break many of the tests that depend on writes.
Note that queries are not currently working w/ the this change.
Jason Wilder
Paul Dix