[SPARK-11695][CORE] Set s3a credentials

Set s3a credentials when creating a new default hadoop configuration.

Author: Chris Bannister <chris.bannister@swiftkey.com>

Closes #9663 from Zariel/set-s3a-creds.

core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala

@@ -92,10 +92,15 @@ class SparkHadoopUtil extends Logging {
       // Explicitly check for S3 environment variables
       if (System.getenv("AWS_ACCESS_KEY_ID") != null &&
           System.getenv("AWS_SECRET_ACCESS_KEY") != null) {
-        hadoopConf.set("fs.s3.awsAccessKeyId", System.getenv("AWS_ACCESS_KEY_ID"))
-        hadoopConf.set("fs.s3n.awsAccessKeyId", System.getenv("AWS_ACCESS_KEY_ID"))
-        hadoopConf.set("fs.s3.awsSecretAccessKey", System.getenv("AWS_SECRET_ACCESS_KEY"))
-        hadoopConf.set("fs.s3n.awsSecretAccessKey", System.getenv("AWS_SECRET_ACCESS_KEY"))
+        val keyId = System.getenv("AWS_ACCESS_KEY_ID")
+        val accessKey = System.getenv("AWS_SECRET_ACCESS_KEY")
+
+        hadoopConf.set("fs.s3.awsAccessKeyId", keyId)
+        hadoopConf.set("fs.s3n.awsAccessKeyId", keyId)
+        hadoopConf.set("fs.s3a.access.key", keyId)
+        hadoopConf.set("fs.s3.awsSecretAccessKey", accessKey)
+        hadoopConf.set("fs.s3n.awsSecretAccessKey", accessKey)
+        hadoopConf.set("fs.s3a.secret.key", accessKey)
       }
       // Copy any "spark.hadoop.foo=bar" system properties into conf as "foo=bar"
       conf.getAll.foreach { case (key, value) =>