Update consul to latest version

bundled version is 0.9.0 newest available is currently 1.6.1

https://github.com/hashicorp/consul/blob/v1.0.0/CHANGELOG.md

It's probably worthwhile to get this out before PG HA becomes widespread.

Need to check with production as well. I believe they're currently running 0.9.0, not from omnibus. It should be backwards compatible, but would need to verify that.