[SPARK-5661]function hasShutdownDeleteTachyonDir should use shutdownDeleteTachyonPaths to determine whether contains file

hasShutdownDeleteTachyonDir(file: TachyonFile) should use shutdownDeleteTachyonPaths(not shutdownDeletePaths) to determine Whether contain file. To solve it ,delete two unused function.

Author: xukun 00228947 <[email protected]>
Author: viper-kun <[email protected]>

Closes #4418 from viper-kun/deleteunusedfun and squashes the following commits:

87340eb [viper-kun] fix style
3d6c69e [xukun 00228947] fix bug
2bc397e [xukun 00228947] deleteunusedfun

Author: viper-kun

core/src/main/scala/org/apache/spark/util/Utils.scala

@@ -213,8 +213,8 @@ private[spark] object Utils extends Logging {
   // Is the path already registered to be deleted via a shutdown hook ?
   def hasShutdownDeleteTachyonDir(file: TachyonFile): Boolean = {
     val absolutePath = file.getPath()
-    shutdownDeletePaths.synchronized {
-      shutdownDeletePaths.contains(absolutePath)
+    shutdownDeleteTachyonPaths.synchronized {
+      shutdownDeleteTachyonPaths.contains(absolutePath)
     }
   }