move the "show version" CLI command from cli.c to asterisk.c so that only one

file depends on version.h, and thus, only one file has to be rebuilt when
version.h gets regenerated (issue #6942)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@23229 65c4cc65-6c06-0410-ace0-fbb531ad65f3