Integrated: JDK-8262926 JDK-8260966 broke AIX build

[Sebastian Stenzel]

Fixed access modifier of `isExtendedAttributesEnabled` which has been moved to super class.

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Commit messages:
 - fixed wrong access modifier

Changes: https://git.openjdk.java.net/jdk/pull/2805/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2805&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262926
  Stats: 3 lines in 1 file changed: 0 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2805.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2805/head:pull/2805

PR: https://git.openjdk.java.net/jdk/pull/2805