[VOL-1825] Implemetation of the reconcile feature in the Core

This commit implements the reconcile feature in the Core as
well as the necessary changes in the GO libraries.  Changes were
also made in the simulated OLT and ONU adapters to react to a
reconcile request following an adapter restart. These changes
were tested in a 1-node deployment (1 core pair) and 3-nodes
deployment (3 core-pairs but single adapter instances).  Test
was also done using the openolt to ensure the reconcile request
does not cause panic in the Core or Openolt since the reconcile
feature is not implemented in Openolt.

Change-Id: I178d619fbcfcc6caa0ee3abfd70fc03c384c5fea
diff --git a/rw_core/utils/core_utils.go b/rw_core/utils/core_utils.go
index c9cd56d..aad1348 100644
--- a/rw_core/utils/core_utils.go
+++ b/rw_core/utils/core_utils.go
@@ -41,6 +41,9 @@
 //If no errors is found then nil is returned.  This method also takes in a timeout in milliseconds. If a
 //timeout is obtained then this function will stop waiting for the remaining responses and abort.
 func WaitForNilOrErrorResponses(timeout int64, chnls ...chan interface{}) []error {
+	if len(chnls) == 0 {
+		return nil
+	}
 	// Create a timeout channel
 	tChnl := make(chan *interface{})
 	go func() {