sync: use io_u_log_error() for more detailed error messages

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/engines/sync.c b/engines/sync.c
index 41612df..48aafff 100644
--- a/engines/sync.c
+++ b/engines/sync.c
@@ -63,8 +63,10 @@
 			io_u->error = errno;
 	}
 
-	if (io_u->error)
+	if (io_u->error) {
+		io_u_log_error(td, io_u);
 		td_verror(td, io_u->error, "xfer");
+	}
 
 	return FIO_Q_COMPLETED;
 }