diagnostics doesn't need to search for perldelta.pod in pre-5.005 locations.

diagnostics doesn't need to search for perldelta.pod in pre-5.005 locations.

Pods are installed into privlib. Before Perl 5.005, privlib didn't contain
the version number in it, so 5.004 and 5.003 (etc) both installed to the same
directory. perldiag.pod differed in not-quite compatible ways, so hacks were
put in to (a) also install it in privlib with the version number in the
filename (b) to hard link it to archlib, which always did contain the version
number.

5.005 changed privlib to contain the version number, solving the underlying
problem (strictly commit bfb7748a896459cc, described here:
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-07/msg00136.html )

Commit a841533b5cf319b3 (Oct 2009) removed the first installation hack,
Commit e8ea61279d90dbe9 (Jul 1998) removed the second.

Hence the code to search in the "hacked" locations is no longer needed,
and in the interests of clarity, should go.