list the move of the astvarrundir from /var/run to /var/run/asterisk

(actually its $(localstatedir)/run/asterisk

Makes setups with asterisk as non-root easier to manage because you can
setup permissions on this dir instead of touching a file and setting 
permissions on that.
Files that come to mind are asterisk.pid and asterisk.ctl socket.

Prodded by and ok @russell


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@180898 65c4cc65-6c06-0410-ace0-fbb531ad65f3