Remove debug/broken assert() in the IOPS logging code

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.c b/stat.c
index c921f5f..851cc2c 100644
--- a/stat.c
+++ b/stat.c
@@ -1313,10 +1313,8 @@
 
 	add_stat_sample(&ts->iops_stat[ddir], iops);
 
-	if (td->iops_log) {
-		assert(iops);
+	if (td->iops_log)
 		add_log_sample(td, td->iops_log, iops, ddir, 0);
-	}
 
 	fio_gettime(&td->iops_sample_time, NULL);
 	td->stat_io_blocks[ddir] = td->this_io_blocks[ddir];