jbd2: Fix a debug message in do_get_write_access()

'buffer_head' should be 'journal_head'

This is a port of a patch which Namhyung Kim <namhyung@gmail.com> made
to fs/jbd to jbd2.

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

fs/jbd2/transaction.c

@@ -589,7 +589,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
 	transaction = handle->h_transaction;
 	journal = transaction->t_journal;
 
-	jbd_debug(5, "buffer_head %p, force_copy %d\n", jh, force_copy);
+	jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
 
 	JBUFFER_TRACE(jh, "entry");
 repeat: