totemudp: Move udp bind() so that multicast works with IPv6

It seems that the IPv6 multicast parameters only take effect when bind()
is called, so I've moved the mcast recv socket bind() to the bottom of
totemudp_build_sockets_ip().

Signed-off-by: Christine Caulfield <ccaulfie@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>