ext4: do not destroy ext4_groupinfo_caches if ext4_mb_init() fails

Caches from 'ext4_groupinfo_caches' may be in use by other mounts,
which have already existed.  So, it is incorrect to destroy them when
newly requested mount fails.

Found by Linux File System Verification project (linuxtesting.org).
Signed-off-by: NAndrey Tsyvarev <tsyvarev@ispras.ru>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>

fs/ext4/mballoc.c

@@ -2617,7 +2617,7 @@ int ext4_mb_init(struct super_block *sb)
 	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
 	if (sbi->s_locality_groups == NULL) {
 		ret = -ENOMEM;
-		goto out_free_groupinfo_slab;
+		goto out;
 	}
 	for_each_possible_cpu(i) {
 		struct ext4_locality_group *lg;
@@ -2642,8 +2642,6 @@ int ext4_mb_init(struct super_block *sb)
 out_free_locality_groups:
 	free_percpu(sbi->s_locality_groups);
 	sbi->s_locality_groups = NULL;
-out_free_groupinfo_slab:
-	ext4_groupinfo_destroy_slabs();
 out:
 	kfree(sbi->s_mb_offsets);
 	sbi->s_mb_offsets = NULL;