ext4: remove unused ac_ex_scanned

When looking at a bug report with:

> kernel: EXT4-fs: 0 scanned, 0 found

I thought wow, 0 scanned, that's odd?  But it's not odd; it's printing
a variable that is initialized to 0 and never touched again.

It's never been used since the original merge, so I don't really even
know what the original intent was, either.

If anyone knows how to hook it up, speak now via patch, otherwise just
yank it so it's not making a confusing situation more confusing in
kernel logs.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -4008,8 +4008,7 @@ static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
 			(unsigned long)ac->ac_b_ex.fe_len,
 			(unsigned long)ac->ac_b_ex.fe_logical,
 			(int)ac->ac_criteria);
-	ext4_msg(ac->ac_sb, KERN_ERR, "%lu scanned, %d found",
-		 ac->ac_ex_scanned, ac->ac_found);
+	ext4_msg(ac->ac_sb, KERN_ERR, "%d found", ac->ac_found);
 	ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
 	ngroups = ext4_get_groups_count(sb);
 	for (i = 0; i < ngroups; i++) {

fs/ext4/mballoc.h

@@ -175,8 +175,6 @@ struct ext4_allocation_context {
 	/* copy of the best found extent taken before preallocation efforts */
 	struct ext4_free_extent ac_f_ex;
 
-	/* number of iterations done. we have to track to limit searching */
-	unsigned long ac_ex_scanned;
 	__u16 ac_groups_scanned;
 	__u16 ac_found;
 	__u16 ac_tail;