Update core/src/main/scala/org/apache/spark/shuffle/IndexShuffleBlockResolver.scala

If we have a failure during block migration, log the exception.

Co-authored-by: Attila Zsolt Piros <2017933+attilapiros@users.noreply.github.com>

Author: holdenk

core/src/main/scala/org/apache/spark/shuffle/IndexShuffleBlockResolver.scala

@@ -226,6 +226,7 @@ private[spark] class IndexShuffleBlockResolver(
 
       override def onFailure(streamId: String, cause: Throwable): Unit = {
         // the framework handles the connection itself, we just need to do local cleanup
+        logWarning(s"Error while uploading $blockId", cause)
         channel.close()
         fileTmp.delete()
       }