Fix bug in --copy-unsafe that made it totally broken, and re-enable

the tests that tested it.  As far as I can tell, it was always broken
since the day I put it in years ago.  In my investigation into this I
was unable to figure out what in the world I was thinking back then,
to introduce a global variable with the wrong information in it rather
than using a parameter that was already available in readlink_stat
function.  That still bothers me a bit but I decided to stop worrying
about it.