Log Message:
Update sysutils/consul to 0.9.3.

FEATURES:
- LAN Network Segments: (Consul Enterprise) Added a new Network Segments
  capability which allows users to configure Consul to support segmented
  LAN topologies with multiple, distinct gossip pools.
- WAN Join for Cloud Providers: Added WAN support for retry join for
  cloud providers via go-discover, including Amazon AWS, Microsoft
  Azure, Google Cloud, and SoftLayer. This uses the same "provider" syntax
  supported for `-retry-join` via the `-retry-join-wan` configuration.
- RPC Rate Limiter: Consul agents in client mode have a new `limits`
  configuration that enables a rate limit on RPC calls the agent makes
  to Consul servers.

IMPROVEMENTS:
- agent: Switched to using a read lock for the agent's RPC dispatcher,
  which prevents RPC calls from getting serialized.
- agent: When joining a cluster, Consul now skips the unique node ID
  constraint for Consul members running Consul older than 0.8.5. This
  makes it easier to upgrade to newer versions of Consul in an existing
  cluster with non-unique node IDs.
- build: Upgraded Go version to 1.9.
- server: Consul servers can re-establish quorum after all of them
  change their IP addresses upon a restart.

BUG FIXES:
- agent: Fixed an issue with consul watches not triggering when ACLs are
  enabled.
- agent: Updated memberlist library for a deadlock fix.
- agent: Fixed a panic when retrieving NS or SOA records on Consul
  clients (non-servers). This also changed the Consul server list to
  come from the catalog and not the agent's local state when serving these
  requests, so the results are consistent across a cluster.
- cli: Updated the CLI library to pull in a fix that prevents all
  subcommands from being shown when showing the agent's usage list; now
  just top-level commands are shown.
- server: Fixed an issue with Consul snapshots not saving on Windows
  because of errors with the `fsync` syscall.