net-firewall/firewalld: Version bump to 0.6.3
Handle a bunch of overdue changes at the same time:
- Depend on net-firewall/nftables (see upstream commit
7fc4b6cfb52c)
- Switch to python-single-r1 (see upstream commit
6d5c0c61fe04)
- Check for required kernel options (bug 540110)
- Update OpenRC init file (bug 654706)
Closes: https://github.com/gentoo/gentoo/pull/10033
Closes: https://bugs.gentoo.org/540110
Closes: https://bugs.gentoo.org/654706
Closes: https://bugs.gentoo.org/662314
Signed-off-by: Matt Turner <mattst88@gentoo.org>