ocfs2: remove pointless assignment from ocfs2_calc_refcount_meta_credits()

The assigned value is never used.

Coverity-id 1226847.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/refcounttree.c

@@ -2428,8 +2428,6 @@ static int ocfs2_calc_refcount_meta_credits(struct super_block *sb,
 			get_bh(prev_bh);
 		}
 
-		rb = (struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
-
 		trace_ocfs2_calc_refcount_meta_credits_iterate(
 				recs_add, (unsigned long long)cpos, clusters,
 				(unsigned long long)le64_to_cpu(rec.r_cpos),