[0.12] CREATE DATABASE WITH SHARD DURATION yields unexpected error

[rkuchan]

When I create a new database with a new retention policy and only include SHARD DURATION, I get an unexpected error. I must include either DURATION or REPLICATION to prevent the error.

> CREATE DATABASE testdb4 WITH SHARD DURATION 30m
ERR: error parsing query: found SHARD, expected DURATION, REPLICATION, SHARD, NAME at line 1, char 30

The queries below did not return errors, so I expected the query above to work:

> CREATE DATABASE testdb1 WITH DURATION 1d
> CREATE DATABASE testdb2 WITH REPLICATION 1
> CREATE DATABASE testdb3 WITH NAME lalala