Remove expired ports:
2016-09-30 math/why3-spark: Only useful for deprecated lang/spark
2016-09-30 lang/spark: Broken for more than 6 months
2016-09-30 math/alt-ergo-spark: Only useful for deprecate lang/spark
2016-09-30 security/nessus-libnasl: Abandoned, consider using OpenVAS
2016-09-30 security/nessus: Abandoned, consider using OpenVAS
2016-09-30 security/nessus-libraries: Abandoned, consider using OpenVAS
2016-09-30 security/nessus-plugins: Abandoned, consider using OpenVAS