refs #91: Fix up case where backoff time is zero

Author: jashmoreAtlassian

java-dynamic-sqs-listener-core/src/main/java/com/jashmore/sqs/retriever/prefetch/PrefetchingMessageRetriever.java

@@ -181,7 +181,7 @@ private ReceiveMessageRequest buildReceiveMessageRequest() {
     @SuppressWarnings("Duplicates")
     @VisibleForTesting()
     int getBackoffTimeInMs() {
-        return PropertyUtils.safelyGetPositiveIntegerValue(
+        return PropertyUtils.safelyGetPositiveOrZeroIntegerValue(
                 "errorBackoffTimeInMilliseconds",
                 properties::getErrorBackoffTimeInMilliseconds,
                 DEFAULT_ERROR_BACKOFF_TIMEOUT_IN_MILLISECONDS