UBIFS: fix compilation warning

Fix the following compilation warning:

fs/ubifs/dir.c: In function 'ubifs_rename':
fs/ubifs/dir.c:972:15: warning: 'saved_nlink' may be used uninitialized
in this function

Use the 'uninitialized_var()' macro to get rid of this false-positive.

Artem: massaged the patch a bit.
Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

fs/ubifs/dir.c

@@ -969,7 +969,7 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
 			.dirtied_ino_d = ALIGN(old_inode_ui->data_len, 8) };
 	struct timespec time;
-	unsigned int saved_nlink;
+	unsigned int uninitialized_var(saved_nlink);
 
 	/*
 	 * Budget request settings: deletion direntry, new direntry, removing