Move the "or_dir" out of any_can_execute_or_dir().

The any_can_execute_or_dir() function checked two things; whether or
not anyone could execute something, and whether or not that thing was
a directory. It's cleaner to have the "is it directory?" check outside
these days, so this commit renames that function to any_can_execute()
and the one place it's used now checks whether or not the argument is
a directory itself.