Don't free the string options

We need at least ->name, just leave them all alone.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/options.c b/options.c
index aeba520..f8e89f3 100644
--- a/options.c
+++ b/options.c
@@ -908,7 +908,9 @@
 	__options_mem(td, 1);
 }
 
-void options_mem_free(struct thread_data *td)
+void options_mem_free(struct thread_data fio_unused *td)
 {
+#if 0
 	__options_mem(td, 0);
+#endif
 }