This deprecated function is only used by ffserver, yet does not have
a prototype visible there.

In the long term, ffserver should be made IPv6-aware.  In the meantime,
this change removes cruft from lavf and fixes some warnings in ffserver.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22329 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b