Evaluate applied-checksum after setting needApplied flag

[anmazzotti]

We are running into some issues when the system-agent tries to re-apply remote plans that have been already applied.

This happens whenever the system-agent is restarted or the entire host is rebooted.

Some logic is already there to suppress re-execution based on secret resource version:

			if w.lastAppliedResourceVersion == secret.ResourceVersion && !wasFailedPlan {
				logrus.Debugf("[K8s] last applied resource version (%s) did not change. running probes, skipping apply.", w.lastAppliedResourceVersion)
				needsApplied = false
			}

However the w.lastAppliedResourceVersion is an in-memory value and a service restart will blank it again.
Therefore evaluating the applied-checksum is a more reliable way for remote plans.

[anmazzotti]

@davidcassany FYI

[Oats87]

@anmazzotti

This is actually intentional behavior. The purpose for this is to force apply a plan if the system-agent is restarted or the node is rebooted.

I would be open to making this configurable; however, as we don't consider this behavior a bug, changing its default behavior is not acceptable

[anmazzotti]

Thank you @Oats87
I pushed an additional commit that introduces a flag to skip remote plans that have been already applied.

Since the flag is false by default this should not impact the current logic.