blktrace: load improvements

- Set the state explicitly to SETTING_UP when loading the
  traces. This could take a while, so tell the status thread
  that we are setting up so it knows how to display us
  correctly.

- Fix a bug with multiple devices where we didn't cache the
  major/minor properly. This made blktrace spend tons of CPU
  cycles looking up /sys.

- Handle multiple devices correctly when adding files.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/iolog.c b/iolog.c
index eeaca29..b8ee067 100644
--- a/iolog.c
+++ b/iolog.c
@@ -323,8 +323,7 @@
 		} else if (r == 2) {
 			rw = DDIR_INVAL;
 			if (!strcmp(act, "add")) {
-				td->o.nr_files++;
-				fileno = add_file(td, fname, 0);
+				fileno = add_file(td, fname, 0, 1);
 				file_action = FIO_LOG_ADD_FILE;
 				continue;
 			} else if (!strcmp(act, "open")) {