Previously libxt_socket.so was included in iptables-mod-tproxy.  It was
missed out when trying to make kmod-ipt-socket and kmod-ipt-tproxy
separate packages

Fixes: 4f443c88 ("netfilter: separate packages for kmod-ipt-socket and kmod-ipt-tproxy")
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>