[ESS] ess related changes in site-lisp break emacs batch mode

[Rodney Sparapani]

Hi Paul: 

You've identified the problem here:
$ find /usr/share/emacs/ -name "cc-defs*"
/usr/share/emacs/21.4/lisp/progmodes/cc-defs.elc

In batch mode, you appear to be compiling .el files which you will not
be able to do if ESS has required cc-defs.el and you don't have it.  
When you are not compiling, cc-defs.elc is all you need.  So, get yourself
cc-defs.el and you should be fine.  This is part of cc-mode.

Thanks, Rodney