Set location of CPAN::Config to /etc/perl as /usr may not be writable.

diff -Naur --exclude=debian perl-5.8.8.orig/lib/CPAN.pm perl-5.8.8/lib/CPAN.pm
--- perl-5.8.8.orig/lib/CPAN.pm	2006-02-01 01:11:22.000000000 +1100
+++ perl-5.8.8/lib/CPAN.pm	2006-02-02 23:49:26.000000000 +1100
@@ -1246,7 +1246,7 @@
 	$configpm = $INC{"CPAN/MyConfig.pm"};
 	$redo++;
     } else {
-	my($path_to_cpan) = File::Basename::dirname($INC{"CPAN.pm"});
+	my($path_to_cpan) = '/etc/perl';
 	my($configpmdir) = File::Spec->catdir($path_to_cpan,"CPAN");
 	my($configpmtest) = File::Spec->catfile($configpmdir,"Config.pm");
 	if (-d $configpmdir or File::Path::mkpath($configpmdir)) {