[PATCH] Change O_DIRECT vs buffered setup

Change the default from O_DIRECT IO to normal buffered IO. That makes
more sense, as O_DIRECT is a special case and should be manually
enabled as such.

Do this by adding a option negate switch, so we don't need two sets
of parameters to control these options.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index 57c0730..a9ee7ab 100644
--- a/HOWTO
+++ b/HOWTO
@@ -277,7 +277,10 @@
 		concurrency.
 
 direct=bool	If value is true, use non-buffered io. This is usually
-		O_DIRECT. Defaults to true.
+		O_DIRECT.
+
+buffered=bool	If value is true, use buffered io. This is the opposite
+		of the 'direct' option. Defaults to true.
 
 offset=siint	Start io at the given offset in the file. The data before
 		the given offset will not be touched. This effectively