Add the IPv6 IP to the TLS cert

For some crazy reason, we've forgotten about trying
to use IPv6 addresses directly with the SSL certificates.

So lets add some logic so clients can connect directly
with the v6 IP.

Change-Id: Ie8b8a2d99945f028bebe805b83bfd863b7b72d57

lib/tls

@@ -234,6 +234,9 @@ function init_cert {
                 # see https://bugs.python.org/issue23239
                 TLS_IP="DNS:$TLS_IP,IP:$TLS_IP"
             fi
+            if [[ -n "$HOST_IPV6" ]]; then
+                TLS_IP="$TLS_IP,IP:$HOST_IPV6"
+            fi
         fi
         make_cert $INT_CA_DIR $DEVSTACK_CERT_NAME $DEVSTACK_HOSTNAME "$TLS_IP"