add missing LWP/Protocol/https10.pm to MANIFEST

Currently LWP::Protocol::https10 is listed in modules/02packages.details.txt.gz to be included in GAAS/libwww-perl-6.01.tar.gz. This means if somebody tries to install ParallelUserAgent (which still depends on LWP::Protocol::https10) via CPAN.pm then a downgrade of libwww-perl may happen.