Log message when legacy IPv6 ICMP protocol name used in SG rule
Log message when legacy IPv6 ICMP protocol name used in SG rule

This way an operator can inform users of new sytax.
Follow-on from comments in https://review.opendev.org/#/c/453346

Change-Id: I5bf934c5d7168bc99df0c9c6d4d4bb851b651f54

openstack/neutron,openstack/neutron,mahak/neutron,openstack/neutron,mahak/neutron,mahak/neutron