Router proxy protocol doesn't work with dual-stack (IPv4 and IPv6) clusters

+++ This bug was initially created as a clone of Bug #2093454 +++

Description of problem:
There is a logic error in the haproxy template code that the "accept-proxy" specifier doesn't get appropriately applied to both IPv4 and IPv6 haproxy interfaces if BOTH IPv4 and IPv6 are enabled.

The "accept-proxy" specifier is added via when the ENV variable ROUTER_USE_PROXY_PROTOCOL is true.

OpenShift release version:
4.11

Cluster Platform:
All

How reproducible:
Always

Steps to Reproduce (in detail):
1. Enable IPv4 and IPv6 via ROUTER_IP_V4_V6_MODE="v4v6" on router deployment
2. Set ROUTER_USE_PROXY_PROTOCOL to true on router deployment
3. RSH into router and confirm that "accept-proxy" is on both "bind :<PORT>" and "bind :::<PORT>" lines for "frontend public" and "frontend public_ssl"


Actual results:
"accept-proxy" is only on "bind :::<PORT>" and missing from "bind :<PORT>"

Expected results:
"accept-proxy" should be on both "bind :<PORT>" and "bind :::<PORT>"

Impact of the problem:
Can't have a dual stack IPv4 and IPv6 configuration with "accept-protocol" on both stacks.