UBIFS: do not update min_idx_lebs in stafs

This is bad because the rest of the code should not depend on it,
and this may hide bugss, instead of revealing them.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c
index 15409815..ac0d2e1 100644
--- a/fs/ubifs/budget.c
+++ b/fs/ubifs/budget.c
@@ -741,7 +741,6 @@
 
 	available = ubifs_calc_available(c, min_idx_lebs);
 	outstanding = c->budg_data_growth + c->budg_dd_growth;
-	c->min_idx_lebs = min_idx_lebs;
 	spin_unlock(&c->space_lock);
 
 	if (available > outstanding)