SPARK-1607. Replace octal literals, removed in Scala 2.11, with hex literals

Octal literals like "0700" are deprecated in Scala 2.10, generating a warning. They have been removed entirely in 2.11. See https://issues.scala-lang.org/browse/SI-7618

This change simply replaces two uses of octals with hex literals, which seemed the next-best representation since they express a bit mask (file permission in particular)