openshift.ks: Stop using lokkit

Declare firewall_allow as an associative array at the bottom of
openshift.ks.  Set protocol:port rules (e.g., udp:53) in this associative
array wherever previously lokkit was used.

Add configure_firewall function, which disables lokkit and writes a basic
ruleset to /etc/sysconfig/iptables.

Add configure_firewall_add_rules, which iterates over ${firewall_allow[@]}
and adds ACCEPT rules to /etc/sysconfig/iptables for the rules defined in
${firewall_allow[@]}.

configure_host: Call configure_firewall.

configure_openshift: Call configure_firewall_add_rules.

restart_services: Restart the iptables service to pick up rules added to
/etc/sysconfig/iptables.