Make verify_dump off by default

It's a change of behaviour, so it should be off by default.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/options.c b/options.c
index 4207537..bb46dc9 100644
--- a/options.c
+++ b/options.c
@@ -1581,7 +1581,7 @@
 		.name	= "verify_dump",
 		.type	= FIO_OPT_BOOL,
 		.off1	= td_var_offset(verify_dump),
-		.def	= "1",
+		.def	= "0",
 		.help	= "Dump contents of good and bad blocks on failure",
 		.parent = "verify",
 	},