ext[234]: fix comment for nonexistent variable

The comment in ext[234]_new_blocks() describes about "i".  But there is no
local variable called "i" in that scope.  I guess it has been renamed to
group_no.

Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ext2/balloc.c

@@ -1315,8 +1315,8 @@ retry_alloc:
 	smp_rmb();
 
 	/*
-	 * Now search the rest of the groups.  We assume that 
-	 * i and gdp correctly point to the last group visited.
+	 * Now search the rest of the groups.  We assume that
+	 * group_no and gdp correctly point to the last group visited.
 	 */
 	for (bgi = 0; bgi < ngroups; bgi++) {
 		group_no++;

fs/ext3/balloc.c

@@ -1572,7 +1572,7 @@ retry_alloc:
 
 	/*
 	 * Now search the rest of the groups.  We assume that
-	 * i and gdp correctly point to the last group visited.
+	 * group_no and gdp correctly point to the last group visited.
 	 */
 	for (bgi = 0; bgi < ngroups; bgi++) {
 		group_no++;

fs/ext4/balloc.c

@@ -1700,7 +1700,7 @@ retry_alloc:
 
 	/*
 	 * Now search the rest of the groups.  We assume that
-	 * i and gdp correctly point to the last group visited.
+	 * group_no and gdp correctly point to the last group visited.
 	 */
 	for (bgi = 0; bgi < ngroups; bgi++) {
 		group_no++;