[PATCH] Don't die if manifind() visits symlinked directory again

Some CPAN distributions, e.g. File-DirCompare-0.7, contains symbolic
links to directories. File::Find::Find(follow=>1) introduced by
commit 686bd545e608c7506ff5a14271feca8457256077 died when
processing such a directory for second time.

This patch allows to visit and report such directories and their
content multiple times (except cycles). This solution instead of
ignoring them was chosen to prevent from getting only one and randomly
selected traversal path to be reported.

Signed-off-by: Chris 'BinGOs' Williams <chris@bingosnet.co.uk>