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/smb1ops.c b/fs/cifs/smb1ops.c
index 725fa61..b170da0 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -63,7 +63,7 @@
 static bool
 cifs_compare_fids(struct cifsFileInfo *ob1, struct cifsFileInfo *ob2)
 {
-	return ob1->netfid == ob2->netfid;
+	return ob1->fid.netfid == ob2->fid.netfid;
 }
 
 static unsigned int