net-mgmt/nfdump: Update to 1.7.8
The following options are no longer available:
- FIXTIMEBUG: discontinued upstream
- GEODB: now always on
- INFLUXDB: discontinued upstream
- NFTRACK: now included in NFPROFILE
- NSEL: now always on
- SFLOW: now always on
Reviewed by: pi
Differential Revision: https://reviews.freebsd.org/D57835