Add MongoDB config server port to cfg

The configuration server port 27019 was missing from the Trove config
files. Add it, and replace the hardcoded version in the guestagent with
a ref to the conf.

Change-Id: Ibca4cbed7669a0fde82af4e3c402f80d24bd9fad
Closes-bug: #1555180

etc/trove/trove.conf.sample

@@ -241,7 +241,7 @@ volume_support = True
 device_path = /dev/vdb
 
 [mongodb]
-tcp_ports = 2500, 27017
+tcp_ports = 2500, 27017, 27019
 volume_support = True
 device_path = /dev/vdb
 num_config_servers_per_cluster = 1

trove/common/cfg.py

@@ -916,7 +916,7 @@ mongodb_group = cfg.OptGroup(
     'mongodb', title='MongoDB options',
     help="Oslo option group designed for MongoDB datastore")
 mongodb_opts = [
-    cfg.ListOpt('tcp_ports', default=["2500", "27017"],
+    cfg.ListOpt('tcp_ports', default=["2500", "27017", "27019"],
                 help='List of TCP ports and/or port ranges to open '
                      'in the security group (only applicable '
                      'if trove_security_groups_support is True).'),

trove/guestagent/datastore/experimental/mongodb/service.py

@@ -256,7 +256,7 @@ class MongoDBApp(object):
     def add_config_servers(self, config_server_hosts):
         """Set config servers on a query router (mongos) instance.
         """
-        config_servers_string = ','.join(['%s:27019' % host
+        config_servers_string = ','.join(['%s:%s' % (host, CONFIGSVR_PORT)
                                           for host in config_server_hosts])
         LOG.info(_("Setting config servers: %s") % config_servers_string)
         self.configuration_manager.apply_system_override(