Update the error message to be object neutral (#515)

The RequeueAfterError error type is a generic error to be used in
case where a requeue is required and not tied to a cluster object.
Thus the message should be generic as well

Author: sidharthsurana

pkg/controller/error/requeue_error.go

@@ -30,5 +30,5 @@ type RequeueAfterError struct {
 
 // Error implements the error interface
 func (e *RequeueAfterError) Error() string {
-	return fmt.Sprintf("requeue cluster in: %s", e.RequeueAfter)
+	return fmt.Sprintf("requeue in: %s", e.RequeueAfter)
 }