Set sin_family to AF_INET when doing lookups, also reset sin_port the first time the ip address changes.

(closes issue #17496)
Reported by: ManChicken

(closes issue #15827)
Reported by: DennisD
Patches:
      dnsmgr_15827.patch uploaded by chappell (license 8)
Tested by: DennisD, gentlec, damage, wimpy


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@270974 65c4cc65-6c06-0410-ace0-fbb531ad65f3