Add new option to asterisk.conf (lockconfdir) to protect conf dir during reloads

(closes issue #16358)
Reported by: raarts
Patches: 
      lockconfdir.diff uploaded by raarts (license 937)
      modified by me


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@243551 65c4cc65-6c06-0410-ace0-fbb531ad65f3