Allow time() syscall in seccomp

Linux 3.12.18 SMP PREEMPT i686 GNU/Linux and glibc-2.18 produces following backtrace upon trying to connect to cjdns with `./contrib/python/cjdnslog ''`: http://bpaste.net/raw/253298/
Register values: http://bpaste.net/raw/253310/
`echo '#include <seccomp.h>' | cpp -dM - | grep ' 13'`: http://bpaste.net/raw/253320/

Added conditional rule for the thing, as suggested in #cjdns