[HOTFIX] Fix Hadoop-1 build caused by #5792.

[harishreedharan]

Replaced fs.listFiles with Hadoop-1 friendly fs.listStatus method.

[vanzin]

LGTM.

[andrewor14]

FsHistoryProviderSuite has passed. I'm merging this into master thanks.

[SparkQA]

Test build #34110 has finished for PR 6619 at commit 6192078.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Params(
  • case class Params(
  • class ElementwiseProduct(val scalingVec: Vector) extends VectorTransformer
  • trait TypeCheckResult
  • case class TypeCheckFailure(message: String) extends TypeCheckResult
  • abstract class UnaryArithmetic extends UnaryExpression
  • case class UnaryMinus(child: Expression) extends UnaryArithmetic
  • case class Sqrt(child: Expression) extends UnaryArithmetic
  • case class Abs(child: Expression) extends UnaryArithmetic
  • case class BitwiseNot(child: Expression) extends UnaryArithmetic
  • case class MaxOf(left: Expression, right: Expression) extends BinaryArithmetic
  • case class MinOf(left: Expression, right: Expression) extends BinaryArithmetic
  • case class Atan2(left: Expression, right: Expression)
  • case class Hypot(left: Expression, right: Expression)
  • case class EqualTo(left: Expression, right: Expression) extends BinaryComparison