Check string length of ts->description, not value

It's no longer a pointer. Fix a buglet in the terse output
printing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/stat.c b/stat.c
index a053c8b..5e0fe43 100644
--- a/stat.c
+++ b/stat.c
@@ -701,10 +701,8 @@
 	log_info("\n");
 
 	/* Additional output if description is set */
-	if (ts->description)
+	if (strlen(ts->description))
 		log_info(";%s", ts->description);
-
-	log_info("\n");
 }
 
 static void sum_stat(struct io_stat *dst, struct io_stat *src, int nr)