Update "mrtg" package to version 2.17.4. Changes since 2.17.2:
- some address fixes to contrib
- fixed duplicate install-sh entry in archive
- set oid-mib-cache file for New_SNMP_util as well #106
- prevent spurious warnings about unknonwn values of inlast outlast in mrtg
- add the process id tmp file extensions, to guard against multiple rateup
  instances messing things up for each other. (attempt to fix #115)
- quell warning in CnTWaLK mode #111
- spelling fixes
- make threshold checking more robust against incomplete information in the
  config file #113
- support ifAlias for Vyatta gear
- CnTWaLK should add the count and not max index
- abort indexmaker if there is no data to be found
- fix for big5 translation
- in cfgmaker use ifdesc=alias only if there is actualy alias info
- fix of a file pointer leak found by coverity scan
- fix for kMG support in rateup
- add support for zyxel ifAlias
- add support for Matrix N7 Diamond
- enable warnings in cfgmaker and fix issues ...
- explicitly import SOCK_DGRAM and AF_UNSPEC to make ipv6 support work
- Updated Net_SNMP_util.pm and SNMP_util.pm to latest versions

(tron)