agent: do not deregister service checks twice (#6168)
agent: do not deregister service checks twice (#6168)

Deregistering a service from the catalog automatically deregisters its
checks, however the agent still performs a deregister call for each
service checks even after the service has been deregistered.
With ACLs enabled this results in logs like:
"message:consul: "Catalog.Deregister" RPC failed to server
server_ip:8300: rpc error making call: rpc error making call: Unknown
check 'check_id'"
This change removes associated checks from the agent state when
deregistering a service, which results in less calls to the servers and
supresses the error logs.
hashicorp/consul,hashicorp/consul,scalp42/consul,scalp42/consul,scalp42/consul,kingland/consul,kingland/consul,scalp42/consul,hashicorp/consul,kingland/consul,42wim/consul,scalp42/consul,42wim/consul,kingland/consul,kingland/consul,42wim/consul,42wim/consul,42wim/consul,hashicorp/consul