manager: recovery from 'policy-loader' failure during reload

The policy-loader process is no longer monitored by the _watchdog method. Whether or not the policy-loader has failed is checked directly in the load_policy_rules verifier method when attempting to load the rules. The verifier will fail if the policy-loader process exits with a return code other than 0. In the event of a failure, the entire resolver will revert to its previous working configuration.