Changing WriteBatcher logging to debug

This is seeming to be too low-level for a user - i.e. user doesn't need to know about a "batcher". The info-level logging we already have that confirms the number of partitions and thread count is of much more value.

Author: rjrudin

src/main/java/com/marklogic/spark/writer/WriteContext.java

@@ -113,7 +113,9 @@ WriteBatcher newWriteBatcher(DataMovementManager dataMovementManager) {
         final int threadCount = getUserDefinedThreadCountPerPartition() > 0 ?
             getUserDefinedThreadCountPerPartition() : getCalculatedThreadCountPerPartition();
 
-        Util.MAIN_LOGGER.info("Creating new batcher with thread count of {} and batch size of {}.", threadCount, batchSize);
+        if (Util.MAIN_LOGGER.isDebugEnabled()) {
+            Util.MAIN_LOGGER.debug("Creating new batcher with thread count of {} and batch size of {}.", threadCount, batchSize);
+        }
         WriteBatcher writeBatcher = dataMovementManager
             .newWriteBatcher()
             .withBatchSize(batchSize)