Only print ts->description if set for non-terse output

Identical to commit 4b0f2258, but for non-terse output.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.c b/stat.c
index 5e0fe43..d310686 100644
--- a/stat.c
+++ b/stat.c
@@ -520,7 +520,7 @@
 					ts->error, ts->verror, (int) ts->pid);
 	}
 
-	if (ts->description)
+	if (strlen(ts->description))
 		log_info("  Description  : [%s]\n", ts->description);
 
 	if (ts->io_bytes[DDIR_READ])