CIFS: Replace netfid with cifs_fid struct in cifsFileInfo

This is help us to extend the code for future protocols that can use
another fid mechanism (as SMB2 that has it divided into two parts:
persistent and violatile).

Also rename variables and refactor the code around the changes.

Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 05f4dc2..2ee5c54 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -1222,7 +1222,7 @@
 	if (!open_file)
 		return get_cifs_acl_by_path(cifs_sb, path, pacllen);
 
-	pntsd = get_cifs_acl_by_fid(cifs_sb, open_file->netfid, pacllen);
+	pntsd = get_cifs_acl_by_fid(cifs_sb, open_file->fid.netfid, pacllen);
 	cifsFileInfo_put(open_file);
 	return pntsd;
 }