Periodically sync services and checks from Nomad to Consul. This is
mostly useful when testing with the Consul dev agent which does not
persist state across restarts. However, this is a reasonable safety
measure to prevent skew between Consul's state and Nomad's
services+checks.
Also modernized the test suite a bit.
Instead of checking Consul's version on startup to see if it supports
TLSSkipVerify, assume that it does and only log in the job service
handler if we discover Consul does not support TLSSkipVerify.
The old code would break TLSSkipVerify support if Nomad started before
Consul (such as on system boot) as TLSSkipVerify would default to false
if Consul wasn't running. Since TLSSkipVerify has been supported since
Consul 0.7.2, it's safe to relax our handling.
