plugin/secondary: fix a bunch of things and tests (#1406)

Fix the error handling. Log when we have an error during any of the
transfer state. And if there isn't an error transfer the zones.

Also fix the tests in test/ so we, at least, check the initial transfer.

Update the docs to show more about how errors are handled.

Ref #1400

plugin/file/secondary.go

@@ -118,19 +118,6 @@ Restart:
 	retry := time.Second * time.Duration(z.Apex.SOA.Retry)
 	expire := time.Second * time.Duration(z.Apex.SOA.Expire)
 
-	if refresh < time.Hour {
-		refresh = time.Hour
-	}
-	if retry < time.Hour {
-		retry = time.Hour
-	}
-	if refresh > 24*time.Hour {
-		refresh = 24 * time.Hour
-	}
-	if retry > 12*time.Hour {
-		retry = 12 * time.Hour
-	}
-
 	refreshTicker := time.NewTicker(refresh)
 	retryTicker := time.NewTicker(retry)
 	expireTicker := time.NewTicker(expire)
@@ -151,7 +138,12 @@ Restart:
 			time.Sleep(jitter(2000)) // 2s randomize
 
 			ok, err := z.shouldTransfer()
-			if err != nil && ok {
+			if err != nil {
+				log.Printf("[WARNING] Failed retry check %s", err)
+				continue
+			}
+
+			if ok {
 				if err := z.TransferIn(); err != nil {
 					// transfer failed, leave retryActive true
 					break
@@ -169,8 +161,13 @@ Restart:
 			time.Sleep(jitter(5000)) // 5s randomize
 
 			ok, err := z.shouldTransfer()
-			retryActive = err != nil
-			if err != nil && ok {
+			if err != nil {
+				log.Printf("[WARNING] Failed refresh check %s", err)
+				retryActive = true
+				continue
+			}
+
+			if ok {
 				if err := z.TransferIn(); err != nil {
 					// transfer failed
 					retryActive = true