jbd2: avoid memleak in jbd2_journal_write_metadata_buffer

The new_bh is from alloc_buffer_head, we should call free_buffer_head to
free it in error case.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240514112438.1269037-2-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>