AMBARI-10059. Start services are failed(SERVICE_CHECK falcon is failed) when adding falcon service on kerberized Ambari 2.0 with enabled NN, HA RM (aonishuk)

ambari-server/src/main/resources/common-services/FALCON/0.5.0.2.1/kerberos.json

@@ -29,7 +29,7 @@
             {
               "name": "falcon_server",
               "principal": {
-                "value": "falcon/${host}@${realm}",
+                "value": "falcon/_HOST@${realm}",
                 "type" : "service",
                 "configuration": "falcon-startup.properties/*.falcon.service.authentication.kerberos.principal",
                 "local_username" : "${falcon-env/falcon_user}"
@@ -50,7 +50,7 @@
             {
               "name": "/spnego",
               "principal": {
-                "value": "HTTP/${host}@${realm}",
+                "value": "HTTP/_HOST@${realm}",
                 "configuration": "falcon-startup.properties/*.falcon.http.authentication.kerberos.principal"
               },
               "keytab": {