Allow netsock2.c to compile on systems that do not define AI_NUMERICSERV.

(closes issue #17617)
Reported by: pprindeville
Patches: 
      asterisk-trunk-bugid17617.patch uploaded by pprindeville (license 347)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@275587 65c4cc65-6c06-0410-ace0-fbb531ad65f3