systemd_git.bb: Add patch to disable --nonet option

Hi I am not particularly happy with this patch but by letting xsltproc
download stylesheets from internet it atleast compiles the thing. But
its very slow. So any better solution if someone has suggestion please
by all means

-Khem

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>