perl-www: Backport CVE-2011-0633 fix

Fixes #187.

This is a backport of perl-www 6.00's fix for CVE-2011-0633. I can't upgrade to 6.0x yet due to some outstanding problems.
Please note that the CVE applies only to HTTPS connections. Perl does not have SSL support in it's core, so perl-www relies on external modules for SSL support, of which there are none included in OpenWRT as of now. I guess it'll be a good idea to incorporate the fix now in case of a future perl SSL inclusion though.

I'll merge the same thing to for-14.07 if this is okay.