recipes/auctex.rcp: Set correct dirs.

If `packagelispdir' and `packagedatadir' are not set then AUCTeX expects
tex-site.el to be in a directory above the actual auctex dir and sets
the variables `TeX-data-directory' and `TeX-lisp-directory' to incorrect
values.  This will prevent such things as correct loading of the styles/
directory.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Merge pull request #1617 from ruediger/auctex-dir-fix

recipes/auctex.rcp: Set correct dirs.