Fix a test that was broken by @pauldix

Add ability to update existing shard spaces.

This will help users recover from influxdata#886. It's dangerous functionality because it only changes the metadata. Will document and tell people to use with caution.

Update the changelog

validate that shard spaces have a non-empty regex

Merge pull request influxdata#832 from influxdb/831-create-shard-space

Make create shard space endpoint database specific.

revert previous commit

update the changelog

fix the build on centos to use recent rocksdb and statically link stdc++

disable arm release until it's fixed

Update CHANGELOG.md