coreutils: changed/removed some of the configure environmental variables

gl_ac_cv_func_link_follows_symlink=no - changed to gl_cv_func_link_follows_symlink
gl_cv_func_mkdir_trailing_slash_bug=no - no longer used
gl_cv_func_rename_dest_exists_bug=no - no longer used
gl_cv_func_rename_trailing_slash_bug=no - no longer used

Signed-off-by: Martin Banky <Martin.Banky@gmail.com>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>