jbd2: delete the duplicated words in the comments

Delete the duplicated words "is" in the comments

Signed-off-by: Yan Wang <wangyan122@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/12087f77-ab4d-c7ba-53b4-893dbf0026f0@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/jbd2/transaction.c

@@ -525,7 +525,7 @@ EXPORT_SYMBOL(jbd2__journal_start);
  * modified buffers in the log.  We block until the log can guarantee
  * that much space. Additionally, if rsv_blocks > 0, we also create another
  * handle with rsv_blocks reserved blocks in the journal. This handle is
- * is stored in h_rsv_handle. It is not attached to any particular transaction
+ * stored in h_rsv_handle. It is not attached to any particular transaction
  * and thus doesn't block transaction commit. If the caller uses this reserved
  * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop()
  * on the parent handle will dispose the reserved one. Reserved handle has to