Log Message:
Updated net/mrtg to 2.16.0

* Makesure mrtg repopulates its cache only once even in fork mode
* Added support for RRDtool based Holt-Winters aberrant behaviour detection.
  Threshold based alerts have been enhanced to be able to fire based on the
  FAILURES RRA. Note that Holt-Winters aberrant behaviour detection can only
  be enabled on newly created RRAs.
* when thresholds were UNboraken, the threshprogok did not run necessarily
* MIB parser rewritten for better compatibility
* allow RouterUptime to contain an explicit OID for queriing the uptime.
* support for nortel passport 8600 in cfgmaker
* Added Documentation for GeTNEXT prefix
* Added New Prefix for Counterd SNMP Walk -> CnTWaLK (see docs)
* Upgrade to SNMP Session 1.10
* Updates for  Net_SNMP_util.pm   and  SNMP_util.pm
* Fix if_is_ciscovlan condition in cfgmaker
* Updated port syntax in documentation (based on trac entry)