RFR: 8262844: (fs) FileStore.supportsFileAttributeView might return false negative in case of ext3 [v3]

[Arno Zeller]

> FileStore.supportsFileAttributeView might return a wrong value for ext3 mounts. In case of newer Linux distributions the extended attributes are enabled by default for ext3 mounts and do not show up /proc/mounts.
> Currently the mount table is parsed to determine whether the mount options contain user_xattr  or nouser_xattr. In case of neither entry it is expected that extended attributes are not supported on ext3. 
> 
> This change removes the special handling for ext3 and ext4 and will always probe the fs if none of the options above are found. This should ensure that we return the right value.

Arno Zeller has updated the pull request incrementally with one additional commit since the last revision:

  Roll back ext4 changes

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2778/files
  - new: https://git.openjdk.java.net/jdk/pull/2778/files/429663ab..833f888e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2778&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2778&range=01-02

  Stats: 17 lines in 1 file changed: 16 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2778.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2778/head:pull/2778

PR: https://git.openjdk.java.net/jdk/pull/2778