Add --output-format command line option

Right now we have normal, terse, and json output. Lets add a parameter
that controls how to output results, instead of having options for
both terse and json outputs. If we are going to add a 4th output
type in the future, it's only going to get more messy.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/filesetup.c b/filesetup.c
index c284071..64da8bb 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -792,7 +792,7 @@
 	 */
 	if (need_extend) {
 		temp_stall_ts = 1;
-		if (!terse_output)
+		if (output_format == FIO_OUTPUT_NORMAL)
 			log_info("%s: Laying out IO file(s) (%u file(s) /"
 				 " %lluMB)\n", td->o.name, need_extend,
 					extend_size >> 20);