HADOOP-19516. S3A: SDK reads content twice during PUT to S3 Express store.

Downgrade warning message from INFO to DEBUG.

Note: this does not fix the apparent issue, merely stops the log message
being printed during single-object PUTs to S3 Express storage.

Contributed by Steve Loughran.

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/UploadContentProviders.java

@@ -286,7 +286,9 @@ public final class UploadContentProviders {
         // the stream has been recreated for the first time.
         // notify only once for this stream, so as not to flood
         // the logs.
-        LOG.info("Stream recreated: {}", this);
+        // originally logged at info; logs at debug because HADOOP-19516
+        // means that this message is very common with S3 Express stores.
+        LOG.debug("Stream recreated: {}", this);
       }
       return setCurrentStream(createNewStream());
     }