Use correct file info (especially inode number) for newly created files

Use correct file info (especially inode number) for newly created files

fhandler_base::open_fs has two problems:
- When newly creating a file, the file info in the path_conv is
  incorrect.  It points to info for the parent dir, not to info
  for the file itself (which, naturally, wasn't available before).
- Fetching the file's inode number only worked for non-NFS.

Both problems should be fixed now by reloading file info if the file
has just been created, as well as using the new FS-agnostic
path_conv::get_ino method.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>