Add new AMI command LocalOptimizeAway.

This command lets you request a "/n" local channel
optimize itself out of the way anyway.

Review: https://reviewboard.asterisk.org/r/732/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@272218 65c4cc65-6c06-0410-ace0-fbb531ad65f3