Regression introduced by 3481d0d dnsmasq: run as dedicated UID/GID
dnsmasq is unable to remove its own pidfile as /var/run/dnsmasq is owned
by root and now dnsmasq runs as dnsmasq:dnsmasq. Change directory
ownership to match.
dnsmasq initially starts as root, creates the pidfile, then drops to
requested non-root user. Until this fix dnsmasq had insufficient
privilege to remove its own pidfile.
Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>