Add 'printing of port number' to mroute_addr_print_ex() for v4-mapped v6.

Add 'printing of port number' to mroute_addr_print_ex() for v4-mapped v6.

For whatever reason, this function never printed port numbers for
IPv6 addresses (but it did for IPv4) - which creates a bit of
confusion for IPv6-mapped v4 addresses on a dual stack socket,
that will have ports numbers printed or not, depending on whether
it's a dual-stack v6 socket or single-stack v4.

This will not(!) add printing of port numbers for "proper" v6
addresses yet, because that might have adverse side effects to address
parsing elsewhere.

Signed-off-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20181207123303.70827-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17996.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 4543b13b8540836f6faf67a03b5358bb8bb94a4a)