[SPARK-10865][SPARK-10866][SQL]Fix bug of ceil/floor, which should returns long instead of the Double type

[chenghao-intel]

Floor & Ceiling function should returns Long type, rather than Double.

Verified with MySQL & Hive.

[chenghao-intel]

test this please

[chenghao-intel]

cc @liancheng

[SparkQA]

Test build #43081 has finished for PR 8933 at commit f5b602a.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • abstract class UnaryMathExpression(val f: Double => Double, name: String)
  • case class Ceil(child: Expression) extends UnaryMathExpression(math.ceil, "CEIL")
  • case class Floor(child: Expression) extends UnaryMathExpression(math.floor, "FLOOR")

[SparkQA]

Test build #1830 has finished for PR 8933 at commit f5b602a.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #43112 has finished for PR 8933 at commit 8dabd91.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • abstract class UnaryMathExpression(val f: Double => Double, name: String)
  • case class Ceil(child: Expression) extends UnaryMathExpression(math.ceil, "CEIL")
  • case class Floor(child: Expression) extends UnaryMathExpression(math.floor, "FLOOR")

[chenghao-intel]

cc @rxin

[davies]

LGTM, merging this into master. Should we also backport it into 1.5?