[go] emit phony for leaf nodes that has no command and doesn't exist.
[go] emit phony for leaf nodes that has no command and doesn't exist.

fixes runtest.rb -n
 auto_vars.mk
 build_once.mk
 command_vars.mk

pombredanne/kati,colincross/kati,pombredanne/kati,shinh/kati,pombredanne/kati,danw/kati,danw/kati,shinh/kati,google/kati,pombredanne/kati,dalinaum/kati,colincross/kati,danw/kati,google/kati,shinh/kati,dalinaum/kati,colincross/kati,google/kati,dalinaum/kati,dalinaum/kati,shinh/kati,google/kati,colincross/kati,colincross/kati,google/kati,colincross/kati,pombredanne/kati,danw/kati,danw/kati,danw/kati,dalinaum/kati,shinh/kati,pombredanne/kati,shinh/kati