Emery Hemingway 1eb37fbe22 VFS: move 'sync' from 'File_system' to 'Directory_service'
The the parent 'Directory_service' interface is reachable from
'Vfs_handle', whereas the 'File_system' interface is not.

Fix #2437
Ref #2422
2017-06-12 14:32:07 +02:00
..