Disable buggy seccomp sandbox code by default

Bug: https://bugs.gentoo.org/443898

--- a/tunables.c
+++ b/tunables.c
@@ -226,7 +226,7 @@
   tunable_isolate_network = 1;
   tunable_ftp_enable = 1;
   tunable_http_enable = 0;
-  tunable_seccomp_sandbox = 1;
+  tunable_seccomp_sandbox = 0;
   tunable_allow_writeable_chroot = 0;
 
   tunable_accept_timeout = 60;