Traffic Router - To support the ${toHostname} pattern when parsing the cr-config

Few variables in the TRAFFIC_ROUTER default profile published at http://trafficcontrol.apache.org/downloads/profiles/2.0.x/default/TRAFFIC_ROUTER_PROFILE.traffic_ops use the pattern ${toHostname}, however, at least till commit 3980b41797c8f2b616277df4b74e73a011c48869, traffic router does not replace this pattern with the ops hostname.