MDL-30381 install_init_dataroot() now creates temp and cache
MDL-30381 install_init_dataroot() now creates temp and cache

This prevents PHP warnings displayed due to recent modifications in
make_temp_dir() and make_cache_dir(). These functions now expect that
the root temp/cache dir already exists. So they must be available before
the lang_installer installs the lang pack during install.

dilawar/moodle