(issue #7256, tzafrir)
Also, update the configure script to make sure that we don't try to build
chan_zap if the installed version of zaptel does not include ZT_EVENT_REMOVED.
git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@58320 65c4cc65-6c06-0410-ace0-fbb531ad65f3