[SPARK-19295][SQL] IsolatedClientLoader's downloadVersion should log the location of downloaded metastore client jars

## What changes were proposed in this pull request?
This will help the users to know the location of those downloaded jars when `spark.sql.hive.metastore.jars` is set to `maven`.

## How was this patch tested?
jenkins

Author: Yin Huai <[email protected]>

Closes #16649 from yhuai/SPARK-19295.

Author: yhuai

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/IsolatedClientLoader.scala

@@ -122,6 +122,7 @@ private[hive] object IsolatedClientLoader extends Logging {
     // TODO: Remove copy logic.
     val tempDir = Utils.createTempDir(namePrefix = s"hive-${version}")
     allFiles.foreach(f => FileUtils.copyFileToDirectory(f, tempDir))
+    logInfo(s"Downloaded metastore jars to ${tempDir.getCanonicalPath}")
     tempDir.listFiles().map(_.toURI.toURL)
   }