verify: Fix latency log for verify commands.

When commands when requeued for the verify operation,
their start time was not reset, resulting in bogus latency graphs.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/backend.c b/backend.c
index 7ec8d2a..0f6e425 100644
--- a/backend.c
+++ b/backend.c
@@ -565,6 +565,8 @@
 			io_u->end_io = verify_io_u;
 
 		ddir = io_u->ddir;
+		if (!td->o.disable_slat)
+			fio_gettime(&io_u->start_time, NULL);
 
 		ret = td_io_queue(td, io_u);
 		switch (ret) {