D5623: fix build against Android NDK (API Level 21 is required)

[Aleix Pol Gonzalez]

apol added a comment.


  +1 LGTM.
  
  Maybe you can specify on the commit message that `attr/xattr.h` isn't present 
on the Android NDK and add a comment on the ifdef wouldn't hurt either.

REPOSITORY
  R286 KFileMetaData

REVISION DETAIL
  https://phabricator.kde.org/D5623

To: mgallien, #android
Cc: apol, #frameworks