resources: Simplify resource Converger and Startup code

This takes the Converged initialization and Startup patterns that are
common in all resources, and bakes it into the core engine. This way
resource writing is much more concise and there is less boilerplate!

resources/sendrecv.go

@@ -108,6 +108,19 @@ func (obj *BaseRes) ReadEvent(ev *event.Event) (exit, send bool) {
 	return true, false // required to keep the stupid go compiler happy
 }
 
+// Running is called by the Watch method of the resource once it has started up.
+// This signals to the engine to kick off the initial CheckApply resource check.
+func (obj *BaseRes) Running(processChan chan event.Event) error {
+	obj.StateOK(false)       // assume we're initially dirty
+	cuid := obj.Converger()  // get the converger uid used to report status
+	cuid.SetConverged(false) // a reasonable initial assumption
+
+	// FIXME: exit return value is unused atm, so ignore it for now...
+	//if exit, err := obj.DoSend(processChan, ""); exit || err != nil {
+	_, err := obj.DoSend(processChan, "")
+	return err // bubble up any possible error (or nil)
+}
+
 // Send points to a value that a resource will send.
 type Send struct {
 	Res Res    // a handle to the resource which is sending a value